Abstract:
The present invention provides an automatic analyzer making it possible to reduce the cost for serum information measurement and prevent a decrease in processing capacity. An automatic analyzer comprises a calorimetric analysis section provided with a reaction vessel to mix a sample with a reagent and a measurement section to measure the color change of the mixture in the reaction vessel; and an electrolyte measurement section to measure the concentrations of electrolytes in a sample, wherein the sample included in the reaction vessel is diluted to be measured in the measurement section of the calorimetric analysis section, and at least one of the degrees of hemolysis, lipemia and icterus in a sample is measured in the electrolyte measurement section.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an electrolyte measuring apparatus and, more particularly, to a measuring method of an automatic analyzer capable of performing calorimetric analysis and electrolyte analysis. 
         [0003]    2. Description of the Related Art 
         [0004]    An electrolyte measuring apparatus measures the concentrations of specified electrolyte components contained in electrolytic solutions from the human body by using ion-selective electrodes. To determine the concentration of an electrolyte component in a sample, the sample or a solution diluted with a dilute solution is supplied to an ion-selective electrode to measure a voltage level. Then (or prior to the above-mentioned measurement), a reference solution with a known ion concentration is supplied to the ion-selective electrode to measure a voltage level. Based on the two voltage levels, the concentration in the sample is calculated. As a method for supplying a sample or diluted solution to an ion-selective electrode, Patent Document 1 (JP-A-6-130070) discloses a system where an electrolyte analysis section is provided in a colorimetric analysis section, a reaction vessel in the calorimetric analysis section is used as a dilution tank for electrolyte measurement, and a thermostatic chamber and agitation mechanism in the calorimetric analysis section are also used for electrolyte measurement. Generally, temperature stability of the measurement solution is important for the electrolyte measurement. The voltage level of the ion-selective electrode varies during measurement depending on the temperature. To secure the data reliability, it is therefore necessary to maintain both sample and reference solution within a range of approximately 37° C.±0.5° C. According to the patent document 1, an electrolyte analysis section is provided in a calorimetric analysis section, a reaction vessel in the calorimetric analysis section is used as a dilution tank for electrolyte measurement and a thermostatic chamber and agitation mechanism in the calorimetric analysis section are also used for electrolyte measurement. In this configuration, both sample and reference solution can be kept under satisfactory temperature control in the thermostatic chamber by using the reaction vessel of the colorimetric analysis section. 
         [0005]    In colorimetric analysis, a sample such as blood and urine is mixed with a reagent, and the resulting color of the mixture is analyzed with a photometer so as to measure the concentration. However, the analysis result may be influenced by the degree of hemolysis, lipemia or icterus in the sample. Therefore, automatic analyzers are provided with the capability to output an index or qualitative judgment indicating the severity of hemolysis, opacity or icterus in the sample as its serum information. In some cases, such serum information, namely hemolysis, opacity or icterus information is measured by using a reagent of analytical item which does not cause absorption of the visible light spectrum. 
       SUMMARY OF THE INVENTION 
       [0006]    However, this conventional method for measuring the serum information has a drawback that another reagent cost arises since it uses the reagent of colorimetric analytical item which does not cause absorption of the visible light spectrum. In addition, measuring the serum information lowers the processing capacity of the calorimetric analysis section. It is an object of the present invention to reduce the cost for serum information measurement without lowering the processing capacity. 
         [0007]    To achieve the above-mentioned object, the present invention provides an automatic analyzer comprising a reaction vessel where a sample is mixed with a diluent; and an agitation mechanism to stir the sample-diluent mixture. The invention is characterized in that a solution prepared by mixing a sample with a diluent is measured in the calorimetric analysis section before the solution is supplied to the electrolyte analysis section for electrolyte analysis. 
         [0008]    According to the present invention, since the calorimetric analysis section can perform serum information measurement and the like by using a diluted sample prepared for electrolyte measurement, it is possible to reduce the running cost of the calorimetric analysis section and raise the processing capacity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  shows an automatic analyzer according to an embodiment of the present invention; 
           [0010]      FIG. 2  shows the flowchart of a process for analyzing an electrolyte and measuring serum information performed by the automatic analyzer of the present invention; and 
           [0011]      FIG. 3  schematically shows the automatic analyzer of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]    The following will describe an embodiment of the present invention with reference to the drawings. 
         [0013]      FIG. 1  illustrates an automatic analyzer according to an embodiment of the present invention. As a whole, the automatic analyzer comprises an analysis unit  123  and a control unit  124 . Its colorimetric analysis section has: a sample disk  115  as a sample feed device which holds a plurality of sample vessels and moves so as to locate each sample vessel to a sample aspiration position; reagent disks  106  and  107  as reagent feed devices each of which holds a plurality of reagent vessels for the respective pertinent analyses and moves so as to locate each reagent vessel to a reagent aspiration position; a reaction vessel  101  for reacting a sample with a reagent therein; a reaction disk  125  functioning as a reaction line having a plurality of reaction vessels  101  arranged circularly thereon; a pipetting mechanism  116  for dispensing a sample to reaction vessels  101 ; reagent pipetting mechanisms  104  and  105  for dispensing reagents to reaction vessels respectively; an agitation mechanism  103  for agitating and mixing a dispensed sample with a dispensed reagent; a multi-wavelength photometer  117  for measuring optical absorptions of reaction liquid in a reaction vessel  101 ; and a cleaning mechanism  102  installed along the reaction disk  125  to clean the reaction vessels  101 . A control section  119  controls the action of each mechanism and the display of the screen. 
         [0014]    The reaction disk  125  is controlled so as to repeat a cyclic operation. In the cyclic operation, the reaction vessel row is rotated by a certain number of reaction vessels and then stopped. The multi-wavelength photometer  117  has a plurality of sensors which are respectively placed so as to detect the corresponding wavelengths. While the reaction disk  125  is rotating, the multi-wavelength photometer  117  detects the light which has passed through the content of a reaction vessel. 
         [0015]    The electrolyte analysis section comprises a reference solution tank  112 ; a diluent tank  113 ; a comparison electrode solution tank  114 ; an electrolytic analysis pipetting mechanism  110  for dispensing a reagent for measuring electrolytes; a sipper mechanism  109  for aspirating a diluted sample (from a reaction vessel  101 ) and the reference solution; and an electrolyte measurement section  108  for performing electrolyte analysis. 
         [0016]    The following describes how the automatic analyzer operates to perform calorimetric analysis/measurement. If an analysis operation start switch disposed on the interface  118  is pressed, the reaction vessel cleaning mechanism  102  begins to clean a reaction vessel  101  and then water blank measurement is performed. The value obtained by this water blank measurement will be used as the reference in the subsequent optical absorption measurement to be done with the reaction vessel  101 . After the cyclic operation of moving the reaction disk  125  by a certain distance and then stopping it is repeated until the cleaned reaction vessel arrives at a sample dispensing position  301 , a sample vessel moves to the sample dispensing position  301 . The two reagent disks  106  and  107  are simultaneously moved so as to locate the respective pertinent analytical reagents to their reagent pipetting positions. Then, the sample pipetting mechanism  116  is operated to aspirate the sample from the sample vessel and then discharge a predetermined amount of the sample into the reaction vessel  101 . Simultaneously, the reagent pipetting mechanism  104  begins to operate to aspirate the reagent from the reagent vessel mounted on the reagent disk  106 . 
         [0017]    Then, this reagent pipetting mechanism  104  moves to the pertinent reaction vessel  101  on the reaction disk  125  and discharges the aspirated predetermined amount of the reagent into it. Then, the reagent pipetting mechanism  104  becomes ready for the subsequent reagent dispensation after it is made clean by the cleaning mechanism (not shown in the figure). After the reagent is dispensed by the reagent pipetting mechanism  104 , the multi-wavelength photometer starts measurement. The measurement is performed when the reaction vessel  101  crosses a light flux during rotation of the reaction disk  125 . After the reagent is added, the reaction vessel  101  moves to an agitation position  303  where the sample is agitated with the reagent by the agitation mechanism  103 . Then, the reagent is added into the reaction vessel  101  by the reagent pitting mechanism  105 , and the mixture is agitated by the agitation mechanism  111 . The reaction vessel  101  successively crosses the light flux due to the rotation of the reaction disk  125 . Each time the reaction vessel  101  crosses the light flux, adsorption of light is measured. After the completion of the measurement, the reaction vessel  101  is made clean by the reaction vessel cleaning mechanism  102  in preparation for measurement of another sample. From the measured optical absorptions, concentrations or enzyme activity values are calculated. The analysis result is indicated by the display section  122 . 
         [0018]    The following describes how the automatic analyzer operates to measure/analyze electrolytes in a sample. After a sample is discharged into a reaction vessel  101  in the same manner as for colorimetric analysis/measurement, the electrolytic analysis pipetting mechanism  110  aspirates a diluent from the diluent tank  113  and dispenses the diluent into the reaction vessel  101  when the reaction vessel  101  with the sample dispensed is placed at a diluent discharge position  302 . Then, when the reaction vessel  101  is moved to a position  303 , the diluted sample is stirred by the agitation mechanism  103 . After that, the reaction vessel moves to a position  304  where the sipper mechanism  109  faces the reaction vessel and aspirates the diluted sample from the reaction vessel into the electrolyte measurement section  108 . Then, the voltage level is measured. 
         [0019]    A control system comprises a control section  119 ; an input section  120  for inputting information; an information storage section  121  for storing the information; and a display section  122  for displaying measured data. In addition, the control system controls the calorimetric analysis section and electrolyte analysis section via an interface  118 . 
         [0020]      FIG. 2  shows a flowchart which is followed by an automatic analyzer according to the present invention when serum information is measured by the calorimetric analysis section for analysis. 
         [0021]    In actual measurement, a sample to be analyzed is dispensed into a reaction vessel  101  by the sample pipetting mechanism  116  when the vessel is at the sample dispensation position  301  (STEP  1 ). Then, the electrolytic analysis pipetting mechanism  110  sips a diluent from the diluent tank  113  and dispenses it into the reaction vessel  101  when the vessel is at the diluent discharge position  302  (STEP  2 ). Then, after the vessel is moved to the position  303 , the diluted sample is stirred by the agitation mechanism  103  (STEP  3 ). The reaction disk  125  is rotated periodically to move the reaction vessel  101  to the position  304 . Each time such a reaction vessel  101  passes the photometer  117 , optical absorptions by the diluted sample are measured (STEP  4 ). To measure the degrees of hemolysis, lipemia and icterus, optical adsorptions are examined at wavelengths 480 nm, 505 nm, 570 nm, 600 nm, 660 nm and 700 nm. The degrees of hemolysis, lipemia and icterus are calculated by the following formula: 
         [0000]      Hemolysis  Hb =(Δ EH−/A )−(Δ EL−/B )− C    
         [0000]      Lipemia  L =(Δ EL/D )− E    
         [0000]      Icterus  I =(Δ EI/E )−(Δ EH/F )−(Δ EL/G )− H      ΔEH: Optical absorption difference between 570 nm and 600 nm   ΔEL: Optical absorption difference between 660 nm and 700 nm   ΔEI: Optical absorption difference between 480 nm and 505 nm   A, B, C, D, E, F, G, H: Correction coefficient
 
Settings of the correction coefficients A, B, C, D, E, F, G and H can easily be changed. The hemolysis, lipemia and icterus judgment thresholds may be set freely.
     
         [0026]    Then, the reaction vessel moves to the position  304  where the sipper mechanism  109  faces the reaction vessel and aspirates the diluted sample from the reaction vessel into the electrolyte measurement section  108 . The voltage level is measured (STEP  5 ). 
         [0027]    From the optical absorptions and voltage level obtained in STEP  4  and STEP  5 , serum information and electrolyte concentrations are respectively output and displayed by the display section  122  (STEP  6 ). 
         [0028]    The measurement of serum information may be performed if electrolyte or serum information measurement is requested for the sample via the interface  118 . Also, the measurement may be performed on any sample regardless of whether or not the measurement is requested. 
         [0029]    Further, the diluent used for the electrolyte measurement section may be a reagent which can be used in the calorimetric analysis section to measure another substance.