Abstract:
The disclosed methods and devices relate to tools for on-site and customizable evaluation of the performance of clinical diagnostic analyzers or automation systems by executing a portable simulation program utilizing actual data from a site of interest. The portable simulation program consists of an Intelligent LIS pre-processor, implementation of a simulation model, and analytical and graphical means to determine and present the performance metrics. This permits a realistic evaluation of the clinical diagnostic analyzers before installing the equipment, thus aiding in making decisions including a decision to buy or appropriately configure clinical diagnostic analyzer. The analysis also allows customers to modify the laboratory setup, improve delivery schedules, with better sample scheduling and storage, and in adding equipment.

Description:
[0001]    This application claims priority from U.S. provisional patent application Ser. Nos. 60/934,649 and 60/945,252 filed on Jun. 15, 2007 and Jun. 20, 2007 respectively, both of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The disclosed methods and devices relate to tools for on-site and customizable evaluation of the performance of clinical diagnostic analyzers or automation systems by executing a portable simulation program utilizing actual data from a site of interest. 
       BACKGROUND 
       [0003]    Estimating the expected performance of clinical laboratory testing and diagnostic systems requires detailed information about the expected workload for accurate capacity planning and performance modeling making such modeling expensive. Clinical laboratory testing and diagnostic systems include components and subsystems that are subject to Food and Drug Administration of the United States or similar regulatory agency in other jurisdictions. Most components cannot be modified to meet regulatory compliance. However, such components can be combined to provide customization and, naturally, this adds to the complexity in carrying out a simulation. Further, highly predictable performance of these systems is required because accuracy and time taken to provide test results may be critical. Thus, investment decisions lead to overcapacity or undercapacity due to inaccurate information about the true needs. Typical assays conducted by such systems cover the spectrum from immunological tests to testing for electrolyte levels, and for metabolites and drugs—including legal and contraband substances, which also contribute to the complexity of evaluating a system for performance in a particular context. 
         [0004]    Laboratories differ significantly in their use of laboratory testing and diagnostic systems. Physicians typically need fast turnaround times for results to allow them to effectively monitor patients under care. For instance, patients with kidney problems or trauma need to be evaluated and monitored to properly manage their electrolyte levels. Further, not all clinical laboratories support all tests or even need the same mix of tests making local considerations important in evaluating analyzers. 
         [0005]    For various reasons, when evaluating clinical diagnostic analyzers, a crude measure—the peak-processing rate—is used to estimate the time and capacity required to process an expected sample workload. This is not a satisfactory solution because it treats other factors as being irrelevant. 
         [0006]    No satisfactory cost effective simulation packages are available for evaluating a clinical diagnostic analyzer of interest. For instance, U.S. Pat. No. 7,076,474 describes a method to simulate a new business process using historical execution data. This method requires the new business process to be represented by a directed graph with various node types such as start nodes, arc nodes, route nodes, work nodes and termination nodes, which require execution data, from which simulation parameters are derived. Such a representation is unnecessarily complex for evaluating clinical diagnostic analyzers. 
         [0007]    United States Patent Publication No. 2006/0031112 discloses a ‘simulation’ that recommends equipment based on similarity to past experiences in providing equipment to other clients. Thus, the method is limited by the need for a database of similarly situated clients and the assumption that the products are improved insignificantly in the interim to allow meaningful comparisons to be made to the database records. More importantly, the method ignores the specific needs or the specific systems being considered. 
         [0008]    United States Patent Publication No. 2007/0078692 discloses a simulation method that uses a hierarchical inverted tree structure to model the process being simulated. A clinical diagnostic analyzer includes loops, such as those formed when samples are reflexed for retesting, and that preclude modeling them as inverted hierarchical trees. 
         [0009]    U.S. Pat. No. 6,768,968 discloses a strategy for estimating the performance of a computer system. While a clinical diagnostic analyzer includes processing power, it is not quite like a computer system in view of its highly specialized properties. The computer is integrated into electrical and mechanical parts for accurately testing biological materials, which is the primary purpose of the device. 
         [0010]    Nevertheless, purchasing decisions attempt to take into account even rough estimates of factors such as the highest patient-reportable result efficiency (First Pass Yield), real-time access to information for proactive diagnosis and remote repair, self-monitoring, intelligent system fault recovery, minimal maintenance, no reagent preparation and calibration stability. First Pass Yield helps reduce non-value-added tasks, which also improves morale and staff retention. Further, it is desirable to have real-time access to information for proactive diagnosis and remote repair to improve uptime and increase productivity. Such systems should also be self-monitoring, with intelligent system fault recovery, few maintenance requirements, and nominal or reduced reagent preparation while displaying calibration stability over a long time period resulting in fewer intervention steps to deliver true walk-away operation. During walk-away operation, the operator may have respite or carry out alternative tasks. 
         [0011]    These features, although valued, are not captured by gross statistics of maximum throughput. Further, back of the envelope estimates do not accurately capture the savings or costs in adopting a particular system. These systems cost in the range of three hundred thousand dollars or more making deployment decisions rather important. 
       SUMMARY 
       [0012]    Applicants recognized the need for evaluation of clinical diagnostic analyzers performance based on local needs.  FIG. 6  and the illustrative graphs for two different sites shown in  FIGS. 4A-B  demonstrate the influence of multiple factors on the performance of a clinical analyzer in a particular place as well the considerable difference in the demands made on the instrument in different contexts. 
         [0013]    Applicants recognized that local needs are preferably approximated by historical or expected test volumes and test type distributions to better estimate the cost of ownership. Applicants have further devised a portable and computationally undemanding tool for practical and quick simulation of just such an evaluation-before the actual system is deployed. This makes it possible to customize design and other details based on tool performance. 
         [0014]    A portable simulation method and system is disclosed for evaluating laboratory testing and diagnostic systems, such as clinical diagnostic analyzers. The disclosed evaluation methods and devices are efficient and cost effective because their evaluation reflects actual expected usage and provides metrics tailored to aid in addressing cost or management issues. The disclosed method and system rely on a simulation, which allows estimation of the performance of a clinical diagnostic analyzer or automation system at each specific customer site before actual deployment. It consists of an Intelligent LIS pre-processor, a simulation model, and analytical and graphical means. Using the disclosed method and systems, the performance of a clinical analyzer or automation system can be estimated with greater precision before the buying decision is made or equipment installed. 
         [0015]    A sales person may use the disclosed method and system using little more than a laptop computer or even a portable memory device encoded with computer executable instructions. With the aid of the disclosed method and system, a potential customer can get a detailed picture of various available options without making extensive investments of time and money. Further, any data provided by the customer continues to be secure in compliance with patient privacy requirements. 
         [0016]    The results of the simulation include a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime. These results allow customers to improve their estimates of resource and capital needs, modify the laboratory setup, adjust delivery schedules, or adding equipment to better meet their needs based on predictable financials while eliminating many of the hidden costs, maintenance and productivity issues. Some preferred embodiments are described below with the aid of illustrative figures, which are briefly described next. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIGS. 1A-B  outline methods for carrying out a preferred simulation implementation. 
           [0018]      FIGS. 2A-B  illustrates some salient features in a preferred preprocessor. 
           [0019]      FIG. 3  shows a flow chart underlying a preferred simulation implementation. 
           [0020]      FIGS. 4A-B  show output graphs showing the turnaround time and the input and output of clinical diagnostic analyzers at different locations. 
           [0021]      FIG. 5  shows an illustrative graph of cumulative and % Turn Around Times in a preferred simulation implementation. 
           [0022]      FIG. 6  shows a Table summarizing the differences in local conditions and use of clinical diagnostic analyzers at different locations requiring prediction of the configuration and type of clinical diagnostic analyzer by a preferred simulation implementation. 
           [0023]      FIG. 7  illustrates the flow of samples through configuration comprising different types of clinical diagnostic analyzer in accordance with rules for controlling the flow of samples and tests. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0024]    Deployment and design decisions relating to clinical diagnostic analyzers are likely to benefit from realistic estimates. For instance, the local conditions may strongly influence the peak throughput for an instrument being considered. The expected frequency and distribution of particular tests is often ignored in evaluating systems because taking them into account requires processing voluminous data. Taking such details into account is likely to improve the evaluation of candidate clinical diagnostic systems. The table in  FIG. 6  demonstrates the influence of multiple factors on the performance of a clinical analyzer in a particular place. This variability is also illustrated by the two example graphs for two different sites shown in  FIGS. 4A-B . 
         [0025]    Although accurate and more realistic estimates aid in configuring and deploying laboratory testing and diagnostic systems, such estimates are expensive and difficult to obtain when reviewing available candidate clinical laboratory testing and diagnostic systems. This difficulty in providing realistic projections of expected use of laboratory testing and diagnostic systems is overcome by this disclosure. Accordingly, now it is possible to deliver predictable financials by eliminating hidden costs, maintenance and productivity issues associated with alternative implementations—provided they are in a timely and cost effective manner. Such estimates are useful in selecting the appropriate configuration and capacity for the clinical diagnostic analyzers or automation systems at each specific customer site. Such estimates allow efficient and effective delivery of healthcare. 
         [0026]    Some of the illustrative tests offered on clinical diagnostic analyzers are listed in the following ASSAY TYPE TABLE. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 ASSAY NAME 
                 ASSAY DESCRIPTION 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 T4 
                 T4, Total T4, Thyroxine 
               
               
                 2 
                 T3Up 
                 T3 Uptake, T3U 
               
               
                 3 
                 CA153 
                 CA 15-3 
               
               
                 4 
                 Myo 
                 Myoglobin 
               
               
                 5 
                 HAVab 
                 HAV Antibody 
               
               
                 6 
                 RubG 
                 Rubella IgG 
               
               
                 7 
                 ToxoG 
                 Toxoplasma IgG 
               
               
                 8 
                 CMVG 
                 CMV IgG 
               
               
                 9 
                 FeT 
                 Ferritin, Iron/Tissue 
               
               
                 10 
                 PSAT 
                 Prostate Specific Antig/Total, PSA 
               
               
                 11 
                 T3T 
                 T3 Total 
               
               
                 12 
                 hCGF 
                 HCG/Free, HCG-CTP 
               
               
                 13 
                 HCVab 
                 HCV Antibody 
               
               
                 14 
                 T4F 
                 T4, Free 
               
               
                 15 
                 T3F 
                 T3, Free 
               
               
                 16 
                 Estr 
                 Estradiol 
               
               
                 17 
                 Prog 
                 Progesterone 
               
               
                 18 
                 TestT 
                 Testosterone, Total 
               
               
                 19 
                 NTelo 
                 N-Telopeptide, NTx, Osteopor 
               
               
                 20 
                 Cort 
                 Cortisol 
               
               
                 21 
                 CA125 
                 CA 125 
               
               
                 22 
                 CEA 
                 CEA, Carcinoembryonic Antigen 
               
               
                 23 
                 Prol 
                 Prolactin 
               
               
                 24 
                 FSH 
                 Follicle Stimulating Hormone, FSH 
               
               
                 25 
                 CKMB 
                 Creatinine Kinase - MB, CKMB, MAss 
               
               
                   
                   
                 CKMB-Isoenzymes 
               
               
                 26 
                 LH 
                 LH, Leutinizing Hormone 
               
               
                 27 
                 Trop 
                 Troponin 
               
               
                 28 
                 T4 
                 T4, Total T4, Thyroxine 
               
               
                 29 
                 T3Up 
                 T3 Uptake, T3U 
               
               
                 30 
               
               
                 31 
                 TSH 
                 TSH, 3rd Gen, High Sensitivity, Thyrotropin 
               
               
                 32 
                 HBSag 
                 HBs Antigen 
               
               
                 33 
                 HIV 
                 HIV (PMA) HIV ½ Antibody 
               
               
                 34 
                 Hbeag 
                 HBe Antigen 
               
               
                 35 
                 Hbeab 
                 HBe Antibody 
               
               
                 36 
                 HBSab 
                 HBs Antibody 
               
               
                 37 
                 Fola 
                 Folate, Folic Acid 
               
               
                 38 
                 B12 
                 Vitamin B12, Cobalamin 
               
               
                 39 
                 HBcMab 
                 HBc Antibody IgM 
               
               
                 40 
                 HAVMag 
                 HAV Antibody IgM 
               
               
                 41 
                 RubM 
                 Rubella IgM 
               
               
                 42 
                 ToxoM 
                 Toxoplasma IgM 
               
             
          
           
               
                 (ASSAY TYPE TABLE CONTINUED) 
               
             
          
           
               
                 43 
                 CMVM 
                 CMV IgM 
               
               
                 44 
                 hCGQl 
                 HCG/Qualitative, bHCG 
               
               
                 45 
                 hCGQn 
                 HCG/Quantitative, bHCG, Total bHCG 
               
               
                 46 
                 AFP 
                 AFP, Alpha Fetoprotein 
               
               
                 47 
                 A1AT 
                 AAT, A1AT, Alpha-1 antitrypsin, a1-protease 
               
               
                   
                   
                 inhibitor 
               
               
                 48 
                 Amph 
                 Amphetamines, Methamphetamine 
               
               
                 49 
                 ApoA1 
                 Apo A1, Apolipoprotein A1 
               
               
                 50 
                 ApoB 
                 Apo B, Apolipoprotein B 
               
               
                 51 
                 ASO 
                 ASO, Antistreptolysin 
               
               
                 52 
                 Barb 
                 Barbiturates, Seconal 
               
               
                 53 
                 Bnzo 
                 Benzodiazepine, Halcion 
               
               
                 54 
                 C3 
                 C3, Complement C3 
               
               
                 55 
                 C4 
                 C4, Complement C4 
               
               
                 56 
                 Caf 
                 Caffeine 
               
               
                 57 
                 ChlL 
                 Cholesterol, LDL 
               
               
                 58 
                 Coca 
                 Cocaine 
               
               
                 59 
                 CRPHS 
                 CRPhs, C-Reactive Protein (high sensitity) 
               
               
                 60 
                 Cycl 
                 Cyclosporin 
               
               
                 61 
                 DDim 
                 D-Dimer, Fibrin degradation fragment 
               
               
                 62 
                 Digit 
                 Digitoxin 
               
               
                 63 
                 FeBT 
                 Iron Binding Capacity/Total, TIBC 
               
               
                 64 
                 FeBU 
                 Iron Binding Capacity/Unsaturated UIBC, 
               
               
                   
                   
                 (Calculated) 
               
               
                 65 
                 FK506 
                 FK506, Tacrolimus 
               
               
                 66 
                 Gent 
                 Gentamicin 
               
               
                 67 
                 Hapt 
                 Haptoglobin 
               
               
                 68 
                 HbA1C 
                 Hemoglobin/Glycated, A1C 
               
               
                 69 
                 Hcyst 
                 Homocysteine 
               
               
                 70 
                 IgA 
                 IgA 
               
               
                 71 
                 IgG 
                 IgG, Gamma Globulin 
               
               
                 72 
                 IgM 
                 IgM 
               
               
                 73 
                 Lipo 
                 Lipoprotein, Lipoprotein A 
               
               
                 74 
                 Mcalb 
                 Microalbumin 
               
               
                 75 
                 Meth 
                 Methadone 
               
               
                 76 
                 NAPA 
                 procainamide/N-propionyl, NAPA 
               
               
                 77 
                 Opia 
                 Opiates 
               
               
                 78 
                 PCP 
                 Phencyclidine, PCP 
               
               
                 79 
                 Preal 
                 Prealbumin 
               
               
                 80 
                 Procai 
                 Procainamide 
               
               
                 81 
                 Quin 
                 Quinidine 
               
               
                 82 
                 RF 
                 Rheumatoid Factor 
               
               
                 83 
                 Siro 
                 Sirolimus, Rapamune 
               
               
                 84 
                 THC 
                 Cannabinoids, THC 
               
               
                 85 
                 Tobra 
                 Tobramycin 
               
               
                 86 
                 Trans 
                 Transferrin 
               
               
                 87 
                 Tricy 
                 Tricyclic Antidepressants 
               
               
                 88 
                 Valp 
                 Valproic Acid, Depakote 
               
               
                 89 
                 Vanco 
                 Vancomycin 
               
               
                 90 
                 Acet 
                 Acetamimophen, Tylenol 
               
               
                 91 
                 Alb 
                 Albumin 
               
               
                 92 
                 ALP 
                 Alkaline Phosphatase 
               
               
                 93 
                 ALT 
                 ALT, SGPT, GPT, Alanine Transaminase 
               
               
                 94 
                 Amy 
                 Amylase 
               
               
                 95 
                 AST 
                 SGOT, AST, Aspartate Transaminase, 
               
               
                   
                   
                 Transferance 
               
               
                 96 
                 BiliD 
                 Bilirubin/Direct, Conjugated 
               
               
                 97 
                 BiliI 
                 Bilirubin/Indirect, Uncongugated 
               
               
                 98 
                 BiliT 
                 Bilirubin/Total 
               
               
                 99 
                 BUN 
                 BUN, Urea Nitrogen, URR 
               
               
                 100 
                 Ca 
                 Calcium 
               
               
                 101 
                 Carb 
                 Carbamazepine, Tegretol 
               
               
                 102 
                 Chl 
                 Cholesterol, Total 
               
               
                 103 
                 ChlH 
                 Cholesterol, HDL 
               
               
                 104 
                 Choli 
                 Cholinesterase 
               
               
                 105 
                 CK 
                 Creatinine Kinase, CK, CPK, CKNac Total 
               
               
                 106 
                 Cl 
                 Chloride, Cl 
               
               
                 107 
                 CO2 
                 C02, Carbon Dioxide 
               
               
                 108 
                 Crea 
                 Creatinine 
               
               
                 109 
                 CRP 
                 CRP, C-Reactive Protein 
               
               
                 110 
                 Dig 
                 Digoxin, Digitalis 
               
               
                 111 
                 Dil 
                 Phenytoin, Dilantin 
               
               
                 112 
                 FeS 
                 Iron/Serum 
               
               
                 113 
                 GGT 
                 GGT, Gamma Glutamyl Transpeptidase 
               
               
                 114 
                 Glu 
                 Glucose 
               
               
                 115 
                 K 
                 Potassium 
               
               
                 116 
                 LA 
                 Lactate, Lactic Acid 
               
               
                 117 
                 LDHIs 
                 Lactate Dehydrogenase, LD, Lactic 
               
               
                   
                   
                 dehydrogenase, LDH, and LDH isoenzymes 
               
               
                 118 
                 Li 
                 Lithium 
               
               
                 119 
                 Lip 
                 Lipase 
               
               
                 120 
                 Mg 
                 Magnesium, Mg 
               
               
                 121 
                 Na 
                 Sodium 
               
               
                 122 
                 NH3 
                 Ammonia 
               
               
                 123 
                 OH 
                 Alcohol/Quantitative 
               
               
                 124 
                 OHQl 
                 Alcohol, Qualitative 
               
               
                 125 
                 P 
                 Phosphorus 
               
               
                 126 
                 PAP 
                 Acid Phosphtase, PAP 
               
               
                 127 
                 Pheno 
                 Phenobarbital, Barbita, Luminal, Solfoton 
               
               
                 128 
                 Prot 
                 Protein, Total Proteins, CSF Protein, Urine 
               
               
                   
                   
                 Protein 
               
               
                 129 
                 Salic 
                 Salicylate, Aspirin 
               
               
                 130 
                 Theo 
                 Theophylline 
               
               
                 131 
                 Trig 
                 Triglyceride 
               
               
                 132 
                 Uric 
                 Uric Acid 
               
               
                 133 
                 Hb 
                 Hb 
               
               
                 134 
                 A1C 
                 A1C 
               
               
                 135 
                 BiliN 
                 Bilirubin/Direct, Conjugated 
               
               
                 136 
                 Propx 
                 Propoxiphine, Darvon 
               
               
                   
               
             
          
         
       
     
         [0027]    The supporting role of clinical diagnostic analyzers in providing a fast turnaround is an important factor in delivering the required level of healthcare. As a result, it is desirable to estimate processing times for relatively urgent samples (the STAT samples) separately from standard samples (the Routine samples) along with an overall combination of the total sample processing. 
         [0028]    A clinical laboratory testing and diagnostic system typically includes a Scheduler, which controls and specifies operations in the analyzer. The Scheduler ensures that samples are accepted from an input queue as resources are reserved for the various expected tests relevant to a particular sample. Unless the required resources are available, a sample continues to be in the input queue. Samples are further batched into trays (or slots) as is shown in  FIG. 3 . In a preferred analyzer model, the sample is aspirated and then sub-samples are taken from this aspirated volume for various tests. The operation of the Scheduler together with the types of tests, for instance the tests listed in the ASSAY TYPE TABLE above, supported by the analyzer provide a reasonably accurate description of an analyzer under consideration. 
         [0029]    Typically such details are not only not available, they are cumbersome to evaluate because of the large number of combinations that reflect different outcomes. As a result, typically parameters such as turnaround time limits are provided to aid in comparing or evaluating the performance of analyzers. Applicants recognized that deploying laboratory testing and diagnostic systems benefits from considering more than just fast turnaround time limits. For instance, one study, summarized in the table presented in  FIG. 6 , of such instruments revealed that clinical diagnostic analyzers handled yearly site volumes of as few as 220 thousand tests to as many as two million tests on each system. Some sites operated the systems round the clock (24 hours) while others operated for as few as eight (8) hours in a day. Chemistry assays, for instance to measure electrolytes like Sodium, Potassium, Carbonate and the like, performed on a single system ranged from about a thousand to more than four thousand in a day. Similarly, for immunoassays, from less than two hundred assays in some settings to more than five hundred assays were carried out on a single system in a day. The turnaround times for the assay results, the time taken from inputting the sample to receiving the output results, ranged from about twenty three (23) minutes to more than an hour while overall throughput and cost or ownership issues were also important factors. 
         [0030]    Significant metrics for evaluating a clinical laboratory testing and diagnostic system include a Maximum Turn Around Time, which is the longest time period from sample arrival to reported test result in a set of samples; the Average Turn Around Time, which is the average time from sample arrival to reported test result; the 95% Turn Around Time (an example of a % Turn Around Time), which is the time under which 95% of the tests will reported; Maximum Throughput, which is the maximum number of tests per hour processed by the system and is the peak value of the sample exit rate in a graph of sample exit rate against time; Downtime, for which the analyzer is not available due to for instance, the need to maintain or calibrate the machine; Walk-Away Time, during which unattended operation is possible; and Arrival and Exit Rate, which may be presented in the form of a graph showing curves representing the arrival rate of test requests into the lab and the rate at which test results are posted by the analyzer (the result rate). These measures may be periodically updated in the form of rolling averages. Further, these metrics may be reported separately for Routine and STAT samples. 
         [0031]    A preferred embodiment uses an Intelligent LIS preprocessor, a simulation model and an analytical and graphical means for providing the estimated performance metrics to a customer prior to the decision to purchase. The simulation is preferably based on data provided by the customer for a representative simulation. Such a simulation-based tool allows improved turn-around times, delivery schedules and rapid identification of desirable modifications to the laboratory setup. 
         [0032]    The preferred embodiment comprises a plurality of components for computerized processing such that the components cooperate to implement the disclosed methods. The components in the system may be hardware, which may include an output device (e.g. a display device such as a screen, monitor or television, or a loudspeaker or telephone), a workstation, an input device (e.g., a keyboard, numerical keypad, dial, touch screen, touch pad, pointing device such as a mouse, microphone or telephone), or software (typically for configuring the hardware), or preferably a combination of hardware and software. 
         [0033]    An exemplary system for implementing the invention comprises two or more components cooperating to implement the methods of the invention in a suitable computing environment, e.g., in the general context of computer-executable instructions. Generally, computer-executable instructions may be organized in the form of program modules, programs, objects, components, data structures and the like. 
         [0034]    An exemplary system for implementing the invention includes a suitably configured general purpose computing device. The invention may be implemented using a wide variety of such devices including personal computers, hand-held devices, multi-processor systems, microprocessor based or programmable consumer electronics, network PCs, minicomputers, and in the form of instructions stored on a portable storage device or media and the like including local or remote memory storage devices. The computing environment preferably includes a hard disk drive for reading from and writing to a hard disk, a magnetic disk drive for reading from or writing to a removable magnetic disk, or an optical disk drive for reading from or writing to a removable optical disk such as a CD ROM or other optical media. It will be appreciated by those skilled in the art that computer readable media which can store data accessible to a computer, such as a removable magnetic disk, and a removable optical disk, magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, random access memories, read only memories, and the like may also be used in the exemplary operating environment. Thus, the computing environment may include computer readable media such as volatile or nonvolatile, removable or non-removable media implemented in any technology or method for information storage such as computer instructions, data structures, program modules and the like. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory, or other memory technology, CD-ROM, CD-RW disks, Digital Versatile Disks (“DVD”) etc. that can be used to store and access the information. Communication media typically includes computer readable instructions, data structures, program modules or data in a modulated data signal such as a carrier wave. These devices are often accessed by the processing unit through an interface, such as a serial port interface that is coupled to the system bus. Increasingly, such devices are being connected by the next generation of interfaces, such as a universal serial bus (USB) with a root hub/Host, and to which other hubs and devices may be connected. Other interfaces that may be used include parallel ports, game ports, and the FireWire, i.e., the IEEE 1394 specification. 
         [0035]    The computing environment may be networked using logical connections to one or more databases and remote computers. The logical connections underlying the computing environment may include a local area network (LAN) and a wide area network (WAN) with wired or wireless links. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet with client-server or peer-to-peer networking protocols. USB provides another way to connect to a network by either using a communication link via a wireless link, a modem, an ISDN connection and the like, or even a hub that can be connected to two computers. The network connections shown are exemplary and do not exclude other means of establishing a communications links. 
         [0036]    In one preferred embodiment, these components comprise a personal computer, such as an IBM PC compatible or another computing platform. The simulation software is preferably coded using JAVA programming language, which allows it to be executed by a large number of computing platforms. Notably, in an actual clinical diagnostic analyzer a component like the Scheduler may be coded using a programming language like C++. The same scheduler performance may be simulated using modules coded in JAVA. It should also be noted that these software implementation features are not intended to limit the scope of the disclosure. 
         [0037]    In a preferred embodiment the input data used for simulation is actual data collected over a period of about a day at the site of interest. Alternatively, the customer or party reviewing the performance of one or more clinical diagnostic analyzer configurations may select or approve the data. It should also be noted that in the following description, the term ‘sample’ actually denotes a pseudo-sample constructed for the purpose of carrying out the simulation rather than being subjected to an actual test. The analyzer definition utilized preferably includes the scheduling details used by an analyzer of interest and the time estimates for various tests and steps carried out. 
         [0038]    In a preferred embodiment the Test arrival rate is updated at one-minute intervals. The computation logic may be represented as: 
         [0000]      If (time now−time simulation start)&lt;1 hour 
         [0000]    
       
         
           
             
               TestArrivalRate 
               ∷ 
             
             = 
             
               
                 NumberofTestRequests 
                 
                   Timenow 
                   - 
                   StartTime 
                 
               
                
               
                 tests 
                 hour 
               
             
           
         
       
     
       Else 
       [0039]    
       
         
           
             
               TestArrivalRate 
               ∷ 
             
             = 
             
               
                 NumberofTestRequestsinLastHour 
                 1 
               
                
               
                   
               
                
               
                 tests 
                 hour 
               
             
           
         
       
     
         [0040]    Similarly, the Results Exit rate is also updated at one-minute intervals: 
         [0000]      If (time now−time simulation start)&lt;1 hour 
         [0000]    
       
         
           
             
               TestResultRate 
               ∷ 
             
             = 
             
               
                 NumberofTestResults 
                 
                   Timenow 
                   - 
                   StartTime 
                 
               
                
               
                   
               
                
               
                 tests 
                 hour 
               
             
           
         
       
     
       Else 
       [0041]    
       
         
           
             
               TestResultRate 
               ∷ 
             
             = 
             
               
                 NumberofTestResultsinLastHour 
                 1 
               
                
               
                   
               
                
               
                 tests 
                 hour 
               
             
           
         
       
     
         [0042]    The test arrival rate (the leading curve) and the results exit rate (the lagging curve) are shown in  FIGS. 4A-B  for two different locations. The x-axis of the graph is the time of day. The time gap between the leading curve and the lagging curve is the Turn Around Time. The difference between a higher leading curve peak and the corresponding lagging curve peak indicates an arrival rate that may be higher than the analyzer&#39;s maximum throughput. Such a difference does not disqualify an analyzer from being suitable. If the Turn Around Time gap does not exceed a specified maximum and the total workload is completed within a specified time, the analyzer may perform satisfactorily at the site of interest. When the leading curve maximum exceeds the corresponding lagging curve maximum, then samples will back up behind the analyzer during this period of the day. The laboratory also can use this curve to determine if the sample arrival schedule needs to be changed. 
         [0043]    An example plot of Cumulative % Turn Around Times is shown in  FIG. 5 . In  FIG. 5 , the graph shows data collected at one-minute intervals. For each minute on the x-axis, the number of samples that have Turn Around Times equal to or less than that minute is totaled and divided by the total number of tests. The resulting percentage is plotted on the y-axis corresponding to the x-axis turn around time. 
         [0044]    The flat line represents 95% of the samples. The curve is a plot of the Cumulative Turn Around Time (the fraction of samples with a Turn Around Time less than the x-axis value) showing that 95% of the samples will have a Turn Around Times of 43 minutes or less, and 100% of the samples will have Turn Around Times of 53 minutes or less, thus allowing visualization of laboratory performance metrics. 
         [0045]      FIG. 1A  illustrates the broad outlines of the preferred embodiment for implementing the simulation. A preferred method for estimating processing of clinical samples at a site, illustrated in  FIG. 1B , preferably comprises preprocessing customer selected input data (step  110  of  FIG. 1B ). Preprocessing of customer selected input data allows the preprocessing functionality to be tailored to the type of data provided by customers while reducing the need to change rest of the design to provide customizable evaluation service for different types of analyzers and data types. 
         [0046]    The preferred method also comprises specifying a clinical diagnostic analyzer to be simulated (step  120  of  FIG. 1B ); selecting at least one parameter (step  130  of  FIG. 1B ) from the group consisting of a test mix, a retest rate, and delay due to retesting; simulating performance of the clinical diagnostic analyzer by executing a simulation software; and providing a measure of the performance of the clinical diagnostic analyzer (step  140  of  FIG. 1B ) in a report including, for pseudo-samples marked Routine or STAT, at least one member of the group consisting of a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime. Advantageously, the method includes a report on the performance metrics including in the form of an Arrival and Exit Rate Graph. A graph of Cumulative and % Turn Around Times may also be provided. 
         [0047]    Preferably, in step  110  the customer selected data is converted into a standard format indicating at least a incoming time, the tests requested, the incubation time and other specifications. If the user does not specify a clinical diagnostic analyzer (in step  120 ), then a default clinical diagnostic analyzer specification is invoked. The parameters for the simulation may include a probabilistic prediction of whether a test result is out of range, and thus requires retesting and other probabilistic measures. These test the system against realistic failure rates. 
         [0048]    Another preferred embodiment implements the simulation software by storing it on a memory device, which can be plugged into or coupled to a computing device with a processor and buffer memory for executing software instructions. The software instructions include commands for executing the simulation software package to evaluate the performance of a clinical diagnostic analyzer based on user approved data and user selected configuration of the clinical diagnostic analyzer, for instance as outlined broadly in  FIGS. 1A-B . Some familiar memory devices are the hard drives in computers, particularly notebook computers, Universal Serial Bus based portable memory devices, floppy disks, Secure Digital Cards, DVDs, CDs and the like. These devices are useful for either being directly coupled to the computing device or for being used as a component to provide the instructions, for instance, by copying, directly or indirectly, the simulation software into a computing device. The simulation software, when executed, preferably causes generation of the report on the performance of the clinical diagnostic analyzer for STAT and Routine samples as well as cumulative measures that do not distinguish between Routine and Stat samples. 
         [0049]    Some preferred metrics in the report include a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime, wherein the report may further include an Arrival and Exit Rate Graph and/or a graph over time of the Cumulative and % Turn Around Times.  FIG. 5  includes an example of the latter. 
         [0050]    Another preferred embodiment is a simulation apparatus for simulating the performance of a clinical diagnostic analyzer. Such an apparatus may be modeled as shown in  FIG. 3 .  FIG. 3  shows a preprocessor for formatting and organizing customer approved input data into a sample worklist. This data includes data corresponding to standard (Routine) and urgent (STAT) samples. Sample data are picked from the sample worklist to generate pseudo samples in accordance with a simulation clock. The pseudo samples are then processed for tests, such as those illustrated in the ASSAY TYPE TABLE, which is not an exhaustive listing but merely indicative of the large number of tests supported by the better clinical analyzers. A detailed description of the preprocessor is provided in  FIGS. 2A-B , which organize the customer-approved data into a Sample Worklist, Analyzer Definitions and Assay Protocols data stores shown in  FIG. 3 . 
         [0051]    The simulation apparatus also includes a simulator consistent with the selected clinical diagnostic analyzer definition. The analyzer definition is essentially a description of the particular analyzer under consideration. This simulator operates as illustrated by  FIG. 3  to allow estimation of the time required for each step while preferably also accounting for the consumables expected to be required for processing the samples. 
         [0052]    Preferably, the simulation apparatus includes a users&#39; interface to provide an output. The output, preferably, includes one or more of the Maximum Turn Around Time, the Average Turn Around Time, the 95% Turn Around Time, the Maximum Throughput, Consumable Usage, the Walk-Away Time, and the Downtime. Further, the output may further include an Arrival and Exit Rate Graph, illustrative example of which are presented in  FIGS. 4A-B . 
         [0053]    A preferred embodiment includes means for preprocessing customer selected input data, for instance, as shown in  FIGS. 2A-B  and  3 ; means for specifying a clinical diagnostic analyzer to be simulated, for instance, with data corresponding to a test mix, delay due to retesting, and downtime; means for simulating performance of the clinical diagnostic analyzer, for instance, as shown in  FIG. 3 ; and means for reporting metrics as the result of the simulation. Such reported metrics may include one or more of the Maximum Turn Around Time, the Average Turn Around Time, the 95% Turn Around Time, the Maximum Throughput, Consumable Usage, the Walk-Away Time, and the Downtime. Preferably these data are illustrated with the help of an Arrival and Exit Rate Graph, an example of which is shown in  FIG. 4 . 
         [0054]    A preferred apparatus for simulating a clinical diagnostic analyzer includes means for providing standardized data from data stored in a data store, the means for providing including any necessary preprocessing of the stored data as illustrated by  FIGS. 2A-B ; means for accessing at least one clinical diagnostic analyzer definition, which is illustrated in  FIG. 3 ; means for identifying assay protocols for processing pseudo-samples extracted from the standardized data; which is also illustrated in  FIG. 3 ; means for scheduling processing of a plurality of pseudo-samples from the pseudo-samples extracted from the standardized data as is illustrated in  FIG. 3 ; means for evaluating whether a test result on the plurality of pseudo-samples requires retesting as is illustrated in  FIG. 3  in the decision box ‘Test Results out of range;’ and means for collecting performance metrics on the plurality of pseudo-samples such as the database ‘Test Process Log’ and the document ‘consumable Usage Statistics’ shown in  FIG. 3 . The performance metrics may include the Maximum Turn Around Time, the Average Turn Around Time, the 95% Turn Around Time, the Maximum Throughput, Consumable Usage, the Walk-Away Time, and the Downtime. The performance metrics may be presented with the aid of an Arrival and Exit Rate Graph. 
         [0055]    Another preferred embodiment is a software package comprising means for preprocessing customer selected input data; means for specifying a clinical diagnostic analyzer to be simulated with data collected for at least one member of the group consisting of a test mix, delay due to retesting, and downtime; means for simulating performance of the clinical diagnostic analyzer; and means for reporting data collected in the simulation for at least one of standard samples, urgent samples and combined standard and urgent samples, wherein the means for reporting data include at least one member of the group consisting of a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime, wherein the means for reporting data may further include an Arrival and Exit Rate Graph and a Cumulative Turn Around Time Graph. 
         [0056]    Means for preprocessing customer selected input data generate standardized input from the customer selected data. If the customer selected data is already in a form acceptable to the means for simulating performance, then no conversion of the data into another form is required. Else, the selected data is transformed into a format suitable for the means for simulating performance. 
         [0057]    Means for specifying a clinical diagnostic analyzer to be simulated allow selection of an analyzer from a list of analyzers for which simulation details are available. In a preferred embodiment, further, the properties of a newly specified analyzer may be input, for instance by specifying the supported operations, the time taken for the steps in each of the supported operations and the error and retesting rates. 
         [0058]    Means for simulating performance compute the estimated time taken to perform various operations depending on the customer selected input data, which includes a specification of the tests to be performed. The time taken for each of the steps is conveniently estimated from the Scheduler in the clinical analyzer of interest and the expected frequency of retesting and errors. A Scheduler in a clinical diagnostic analyzer specifies the operations to be carried out at a particular time on a particular sample in order to perform a specified assay. It also receives confirmation that the specified operations were carried out at the proper time in its role as a controller. If the specified operation was not performed, or performed too late, the Scheduler may detect the error and flag the affected result. Thus, it has the appropriate information about the time taken to perform an assay. 
         [0059]    In preferred embodiments the frequency of retesting and the error rates may be further specified to better evaluate the effect of such parameters on the performance of the clinical analyzer of interest. The means for simulating performance adds the times and resources required for various operations to arrive at statistics and performance metrics for the clinical analyzer of interest. 
         [0060]    Means for reporting data collected in the simulation provide reports for standard samples and urgent samples. In a preferred embodiment, the urgent samples may be highlighted or otherwise distinguished, including when a combination of standard and urgent samples is presented to the clinical analyzer of interest. In a preferred embodiment, the output data from the means for reporting data include at least one member of the group consisting of a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime, wherein the means for reporting data may further include an Arrival and Exit Rate Graph and a Cumulative Turn Around Time Graph. These parameters help describe the performance of the analyzer and provide an estimate of the cost of ownership of the clinical analyzer of interest. 
         [0061]    The disclosed embodiments include an apparatus. Such an apparatus for simulating a clinical diagnostic analyzer comprises means for providing standardized data from data stored in a data store, the means for providing standardized data including any necessary preprocessing of the stored data; means for accessing a clinical diagnostic analyzer definition to provide a definition of at least one clinical diagnostic analyzer; means for identifying assay protocols for processing pseudo-samples extracted from the standardized data; means for scheduling processing to order steps for processing a plurality of pseudo-samples from the pseudo-samples extracted from the standardized data; means for evaluating retesting to detect whether a test result on the plurality of pseudo-samples requires retesting; means for collecting performance metrics on the plurality of pseudo-samples, wherein the performance metrics are selected from the group consisting of a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime, wherein the means for collecting performance metrics may further include an Arrival and Exit Rate Graph and a Cumulative Turn Around Time Graph. 
         [0062]    Means for providing standardized data convert the customer selected data into a standardized format. If the customer selected data is already in an acceptable form, then no conversion of the data into another form is required. 
         [0063]    Means for accessing a clinical diagnostic analyzer definition provide access to either a default clinical diagnostic analyzer definition or to a particular clinical diagnostic analyzer definition. In most instances, it is expected that such a definition includes timing details underlying Scheduler operations. Such means may be in the form of an electronic memory or be implemented as part of a user interface designed to accept a clinical diagnostic analyzer definition, including by specifying a memory location or data structure with the required information. 
         [0064]    Means for identifying assay protocols allow specification of the supported assays. Some exemplary assays are listed in the ASSAY TYPE TABLE. This illustrative listing is not limiting as additional or fewer than the listed assays may be supported on a particular analyzer, including based on local needs or business consideration. Such means may be in the form of an electronic memory or be implemented as part of a user interface designed to accept a specification of supported assays. 
         [0065]    Means for scheduling processing allows estimation of the steps and the time and other resources required for processing of the samples. 
         [0066]    Means for evaluating retesting make the simulation more realistic by allowing incorporation of expected error rates and the retesting due to errors to better evaluate the performance of the analyzer. Retesting decision making is also illustrated in  FIG. 3 . 
         [0067]    Means for collecting performance metrics collects and organizes the data on time and resources required for the simulated run to efficiently communicate the performance of the analyzer in the context of cost and management decision making. Some example metrics reportable by a preferred embodiment include one or more of a Maximum Turn Around Time, an Average Turn Around Time, a 95% Turn Around Time, a Maximum Throughput, Consumable Usage, a Walk-Away Time, and a Downtime, wherein the means for collecting performance metrics may further include an Arrival and Exit Rate Graph and a Cumulative Turn Around Time Graph.  FIG. 3  illustrates the time and consumable usage data collection for generating metrics of interest. 
         [0068]    One skilled in the art will appreciate embodiments include estimating the performance of not just one or a few clinical diagnostic analyzers, but also a plurality of clinical diagnostic analyzers configured to operate together to process an incoming stream of samples. If several clinical diagnostic analyzers of the same type are deployed, then the input samples can just be divided evenly between them. However, if the clinical diagnostic analyzers are of different types, the individual characteristics of the analyzers need to be taken into account to evaluate performance of the entire configuration. One such exemplary embodiment is illustrated in  FIG. 7 . 
         [0069]      FIG. 7  shows a simulation using three different kinds of clinical diagnostic analyzers. 
         [0070]    The first type of clinical diagnostic analyzer handles chemistry assays and immunoassays in an integrated setup with a scheduler to coordinate resource use to improve throughput. An example of such an analyzer is the VITROS 5600™ clinical diagnostic analyzer manufactured by Ortho Clinical Diagnostics®. VITROS 5600™&#39;s Master Scheduler is implemented to support as many as three chemistry platforms: (i) microslides using dry chemistry, (ii) microtips for wet chemistry, and (iii) microwells using wet chemistry. VITROS 5600™ employs a robotic arm and pipettors shared between the various chemistry platforms to provide random access to input patient samples. The robotic arm allows aliquots to be drawn from a single input patient sample for each of the tests carried out on the analyzer, including tests carried out on different platforms integrated into the analyzer. This analyzer supports dry chemistry based tests on microslides for analytes such as Na, K, Cl −  and the like as well as immunoassays and other assays using its microwell and microtip platforms. The second type of clinical diagnostic analyzer, which is also a combinational clinical analyzer, includes fewer platforms. An example of such an analyzer is the VITROS 5,1 FS™ manufactured by Ortho Clinical Diagnostics®. The VITROS 5,1 FS™ supports microslide and microtip based assays only. The third type of clinical diagnostic analyzer has a more limited platform and may have as few as one platform. Examples include analyzers that only support immunoassays, such as VITROS ECi™ and VITROS 3600™ manufactured by Ortho Clinical Diagnostics®. Although clinical diagnostic analyzers manufactured by Ortho Clinical Diagnostics® are described here as preferred, the methods and teachings are applicable to other clinical diagnostic analyzers as well. Accordingly, one having ordinary skill in the art will readily modify the formulae and other criteria described in the examples herein for evaluating configurations based, wholly or in part, on analyzers manufactured by manufacturers other than Ortho Clinical Diagnostics®. 
         [0071]    For the simulation, a strategy similar to Flow  700  outlined in  FIG. 7  may be utilized. In Flow  700 , LIS data is preprocessed to sort it based on the types of assays that are to be carried on each sample. Preferably, each type of clinical diagnostic analyzer uses an input patient sample to carry out one or more types of tests on small aliquots drawn from the sample. Thus, preferably a single sample is not split up between two or more different analyzers to reduce complexity, sample loss, and reduced throughput. 
         [0072]    Input LIS data  705  is evaluated by Parser  710  to identify patient samples requiring tests based on each of microtips, microslides and microwells. These are assigned for processing by the versatile Analyzer I. If multiple Analyzer Is are deployed, then the samples are proportionally reduced (most output parameters can be estimated by simply scaling the performance of a single analyzer) by Reducer  725 . Reducer  725  also tracks samples that cannot be processed by Analyzer II and Analyzer III due to their unavailability as determined in Decision Blocks  730  and  735  because Analyzer I is versatile enough to handle all types of tests. The total number of samples to be processed by Analyzer I are preferably reduced proportionally by Reducer  725  in the simulation for computational efficiency as describe above. 
         [0073]    Input LIS data  705  is evaluated by Parser  715  to identify patient samples requiring tests based on each of microtips and microslides. These are provisionally assigned for processing by Analyzer  2 . Decision Block  730  assigns such samples to Analyzer  1  if no Analyzer  2  is available. If Analyzer  2  is available, Decision Block  740  evaluates the First Condition. 
         [0000]      The number of samples requiring both Chemistry and immunoassays&gt;(the number of samples requiring Chemistry assays)/(Number of analyzers with Chemistry assays capability at Site) 
         [0074]    If the First Condition is not satisfied, some of such samples are assigned to Analyzer  1  via the Reducer  745  and Summation Block  750 , which also receives the output of Reducer  725 . Reducer  745  evaluates the following for making its reduction to generate the input to Summation Block  750 : 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       Total_Samples 
                        
                       _with 
                        
                       _Chem 
                        
                       _Tests 
                     
                     
                       # 
                        
                       
                           
                       
                        
                       Analyzers_with 
                        
                       _Chem 
                        
                       _Capability 
                     
                   
                   - 
                 
               
             
             
               
                 
                   
                     Samples_with 
                      
                     _IA 
                      
                     _and 
                      
                     _Chem 
                      
                     _Tests 
                   
                   
                     # 
                      
                     
                         
                     
                      
                     Analyzer_ 
                      
                     1 
                      
                     
                         
                     
                      
                     s 
                   
                 
               
             
           
         
       
     
         [0075]    If the First Condition is not satisfied then Reducer  755  proportionally reduces the number of samples based on the number of Analyzer  2   s  to generate part of the sample input for Analyzer  2 . 
         [0076]    If the First Condition is satisfied, then, control flows to Reducer  760 , which proportionally reduces the number of samples based on the number of Analyzer  2   s  to generate the remaining part of the sample input for Analyzer  2 . 
         [0077]    Input LIS data  705  is evaluated by Parser  720  to identify patient samples requiring immunoassays only. These are provisionally assigned for processing by Analyzer  3 . Decision Block  735  assigns such samples to Analyzer  1  if no Analyzer  3  is available. If Analyzer  3  is available, Decision Block  765  evaluates the Second Condition. 
         [0000]      The number of samples requiring both Chemistry and immunoassays&gt;(the number of samples requiring immunoassays)/(Number of analyzers with immunoassay capability at Site) 
         [0078]    If the Second Condition is not satisfied, some of such samples are assigned to Analyzer  1  via the Reducer  770  and Summation Block  750 , which also receives the output of Reducer  725  and Reducer  745 . Reducer  770  evaluates the following for making its reduction to generate the input to Summation Block  750 : 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       Total_Samples 
                        
                       _with 
                        
                       _IA 
                        
                       _Tests 
                     
                     
                       # 
                        
                       
                           
                       
                        
                       Analyzers_with 
                        
                       _IA 
                        
                       _Capability 
                     
                   
                   - 
                 
               
             
             
               
                 
                   
                     Samples_with 
                      
                     _IA 
                      
                     _and 
                      
                     _Chem 
                      
                     _Tests 
                   
                   
                     # 
                      
                     
                         
                     
                      
                     Analyzer_ 
                      
                     1 
                      
                     
                         
                     
                      
                     s 
                   
                 
               
             
           
         
       
     
         [0079]    If the Second Condition is not satisfied then Reducer  775  proportionally reduces the number of samples based on the number of Analyzer  3   s  to generate part of the sample input for Analyzer  3 . 
         [0080]    If the Second Condition is satisfied, then, control flows to Reducer  780 , which proportionally reduces the number of samples based on the number of Analyzer  3   s  to generate the remaining part of the sample input for Analyzer  3 . 
         [0081]    The simulation then computes the performance of the entire configuration by computing the time required for handling the samples, the resources consumed and other output parameters described previously. The respective performance of each of the analyzer types may be computed by using their respective Schedulers as described previously. This approach does not result in a significant performance penalty or require very sophisticated resource hungry implementations for analyzing the performance of relatively complex configurations of clinical diagnostic analyzers. 
         [0082]    One skilled in the art will appreciate that the above disclosure is susceptible to many variations and alternative implementations without departing from its teachings or spirit. The scope of the claims appended below includes such modifications. Further, each reference discussed and cited herein is hereby incorporated herein by reference in its entirety.