bluuebunny/crossref_metadata_2025 huggingface dataset:
A-132 Next generation ammonia reagent with improved reagent composition and assay performance
Authors: Nair S , Chandler S , White L , Acorn R
Published: October 2024

Background

Ammonia is produced by catabolism of protein and other compounds which contain nitrogen. Elevated ammonia levels are toxic for the central nervous system. High plasma ammonia is a prognostic factor for hepatic and kidney disease or inherited metabolic disorders in urea cycle metabolism. The reliable and accurate quantification of ammonia is influenced by assay, reagent, and sample management. Current commercially available GLDH enzyme-based ammonia assay reagents experience high bias between matched Lithium Heparin and K2-EDTA samples, poor accuracy, imprecision at the low end, large HIL (hemolysis, icterus and lipemia) interferences and shorter shelf life. To improve upon the listed deficiencies, we developed an improved GLDH based ammonia assay in a two-part format with improved reagent composition.

Methods

Ammonia reagent in 2-part format R1 and R2 were assessed for accuracy, precision, interference by HIL reportable range, sensitivity (LoB, LoD, LoQ), shelf life, matched matrix comparison (Lithium Heparin vs K2-EDTA) and method comparison. All testing were performed using Li Heparin plasma samples in Beckman DxC700AU analyzer. Accuracy was tested using Verichem ammonia standards which are ACS ammonia standard material. Twenty-day precision studies were performed using three levels of ammonia concentrations using Bio-Rad Liquichek Ammonia controls and plasma samples. Interference was tested in two ammonia concentrations (40-50 µmol/L) and (200-250 µmol/L) using commercially available spiking material for clinical chemistry assays such as conjugated and unconjugated bilirubin, Intralipid and in-house prepared hemolysate. Infinity Ammonia Reagent on Beckman Coulter AU Chemistry Analyzers was used for method comparison studies

Results

Next generation ammonia showed good accuracy with Verichem ammonia standards and acceptable within-run and total precision. Studies showed significant improvement in sensitivity and longer shelf life (>18 months). Next generation ammonia is less affected by interferences from icterus (100 mg/dL), lipemia (1000 mg/dL intralipid) and hemolysis (100 mg/dL). Comparison studies show no significant bias between match Lithium Heparin and K2-EDTA matched samples.

Conclusions

Next Generation Ammonia reagent showed very good overall performance required for reliable and accurate quantification of ammonia in human plasma sample.
A-147 Comparative Precision of Platelet Counting by Optical, Fluorescent, and Impedance Techniques in Thrombocytopenia and Microcytosis Patients
Authors: J H , V G , Pandey S , Sehgal T
Published: October 2024

Background

In today's era of automation driven by Artificial Intelligence, even the most efficient automated hematology analyzer may struggle to accurately determine platelet count in patients with low platelet count and microcytosis. The Sysmex XN-series analyzer (Sysmex, Kobe, Japan) uses optical density, fluorescence, and electronic impedance methods for platelet counting. This study aimed to evaluate the accuracy of optical, fluorescence, and electrical impedance methods in estimating precise platelet counts in thrombocytopenic and microcytic patient samples.

Methods

A cross-sectional study was conducted in the Department of Laboratory Medicine at AIIMS, New Delhi, for 30 days consecutively. A total of 200 blood samples collected, of which 100 samples were of thrombocytopenia (<100x10^9/L) and 100 samples were of microcytosis (Mean corpuscular volume <76 femtoliters). MCV<76 fl was further categorized into 2 groups- MCV 60-70 fl and MCV 71-76 fl accordingly. Males and females were categorized and analyzed distinctly for thrombocytopenia and microcytosis. Statistical analysis was performed using SPSS 16.0 for Windows (SPSS Inc., Chicago, IL, USA) and the Bland Altman plot was analyzed.

Results

Of the 100 patients with thrombocytopenia (platelet<1 lakh/L) females were predominantly 54% while males were 46% and the median age was 29 years (0.02-70). Of the 100 patients with low MCV (<76 fl) females were 53%, while males were 47% and the median age was 29 years (0.3-69). The findings were compared against the standard manual platelet count method in peripheral smears verified by two expert pathologists. The Bland Altman plot for Platelet <1 lakh/L and MCV <76 fl were compared with standard manual platelet count method and the following findings were obtained i) In female with PLT- <1 lakh/L, PLT-O showed least bias (9.8) followed by PLT-F (10.4) and PLT-I (12.1) ii) In males with PLT-<1 lakh/L, PLT-O showed least bias(14.1) followed by PLT-F(16.5) and PLT-I(17.0) iii) For MCV 61-70fl, PLT-O showed the least bias (4.4) followed by PLT-F (6.7) and PLT-I (28.5) iv)For MCV 71-76fl, PLT-F showed least bias (-0.2) followed by PLT-O (1.5) and PLT-I(31.2).

Conclusions

Platelet count by optical method (PLT-O) detects platelet count more accurately with minimum bias when compared with PLT-F and PLT-I in patients with thrombocytopenia. In patients with microcytosis, PLT-I is less reliable in comparison to PLT-O and PLT-F. A limitation of the automated hematology analyzer is the inability to detect platelet clumps which is appreciated in peripheral smears.
A-163 Stability of apixaban in Li-heparin plasma stored refrigerated over mint green-top tube separator gel
Authors: Stickle D , Eberle-Singh J , Kolowrat S A , Korn W R , Kraft W K
Published: October 2024

Background

Apixaban is a factor Xa inhibitor used as a direct oral anticoagulant (DOAC). The laboratory was asked to provide measurements of plasma apixaban in the context of studies regarding interaction of apixaban with other therapeutic drugs. One study involved isolation of plasma from to-be-discarded specimens, where such specimens were those originally collected in mint green-top tubes (Li-heparin tubes containing plasma separator gel), and that had been centrifuged and stored refrigerated for 5 days. Whereas apixaban concentration is known to be stable in refrigerated plasma specimens for up to two weeks, stability of apixaban concentration in plasma stored refrigerated for prolonged periods over plasma separator gel was unknown. Our objective was to examine stability of apixaban in plasma stored refrigerated for 5 days over plasma separator gel.

Methods

Pharmacy records were reviewed to identify inpatients who were prescribed apixaban, and for whom a mint green-top tube specimen (Becton-Dickinson BD Vacutainer PST Gel and Lithium Heparin, #367961) had been drawn for routine chemistry tests. From such specimens, 500 uL aliquots of plasma were obtained on day 1 (A) and day 5 (B) of storage under refrigeration (4 °C). Apixaban concentrations for A and B were measured by LC-MS/MS and compared. Additionally, short term (1 day) stability of apixaban was examined by comparison of replicate measurements of apixaban in a single spiked pooled purple-top plasma specimen (Becton-Dickinson BD Vacutainer K2 EDTA, #367856), with (C) or without (D) exposure to mint green-top tube separator gel for a 24h refrigeration period. Data analyses were conducted using R (version 4.0.5).

Results

A total of 21 specimen pairs (A, B) were examined. [Apixaban] ranged from 30-1000 ng/mL. The ratio B/A was 1.007 ± 0.034, consistent with no effect on plasma [apixaban] of refrigerated storage over separator gel between day 1 and day 5 (by paired t-test: p>0.8). Experiments for replicates of (C, D) specimens (n = 4, average [apixaban] = 410 ng/mL) gave D/C ratio of 1.009 ± 0.019, consistent with no effect on plasma [apixaban] of short term (1 day) refrigerated storage of plasma over separator gel (by paired t-test: p>0.4).

Conclusions

For plasma specimens collected and centrifuged in mint-green plasma separator tubes, there was no effect on plasma [apixaban] of refrigerated storage over separator gel for periods of 0-5 days.
A-169 Artificial Intelligence based Complete Blood Count
Authors: Tohami T , Bahat S , Isman S , Shbita G , Rashid G
Published: October 2024

Background

The OLO device (Sight diagnostics, Israel) is an artificial intelligence based blood counter. OLO contains a fluorescent microscope and a camera embedded inside it. The pictures are processed by an image processing algorithm based on “machine-vision technology” to identify and quantify cells. The measurement analysis is accompanied by messages (flags) that are used to warn of deviations in the counted parameters, which help the operator refer the sample for microscopic analysis.

In this study, we compared the results of 19 complete blood count (CBC) parameters obtained from OLO to the CBC parameters obtained from the ADVIA 2120 device (Siemens, USA). In addition we examined the reliability of OLO alerts (flags) by comparing it to the microscopic analysis findings.

Methods

99 blood samples from patients aged >3 months were sampled by the ADVIA and OLO devices. Regression analysis was performed in comparing the results of 19 parameters between the devices. Specificity and sensitivity values ​​of the OLO device alerts were calculated.

Results

A good correlation was found for CBC parameters between OLO and ADVIA with Pearson correlation (R) of 0.992 (WBC), 0.985 (RBC), 0.991 (HB) and 0.983 (PLT). A fundamental difference in measurement and classification technologies between OLO and ADVIA lead to low correlation measured for monocytes. By comparing OLO alerts against blood smears findings, a total of 14 samples were alerted by OLO but only slight left shift/single pathological cell were found in the smears which is below threshold defined by the manufacturer. These 14 samples were transferred to the true positive category, therefore OLO device alerts showed sensitivity and specificity of 81.8% and 90% (respectively) in identifying pathological cells.

Conclusions

The comparison findings present a technology based on image processing and artificial intelligence that have a good correlation to the ADVIA reference device. In addition, OLO has the ability to warn of pathological findings even below the threshold defined by the manufacturer. The artificial learning is expected to be improved so that this device can integrate CBC and microscopic differentiation simultaneously, a great advantage to the hematology laboratories workflow.
A-191 Improvement of Outpatient Satisfaction Rate at Specimen Collection Area
Authors: Tamimi W , Alfraj S , AlSaqri F , AlSharari M , Althubiti F M , AlZahrani K , Al-Dhuwaibi E M , Al-Otaibi H M , Al-Khalidi A , Al-Thubaiti T M , Badr El Din R M , AlAjlan A
Published: October 2024

Background

The process of collection of body fluid samples and phlebotomy services require highly professionally staff to deal and ensure the reliability of laboratory services to our outpatients when they visit the lab. Satisfaction of the outpatient is one of the quality indicators to monitor and ensure that the laboratory services are adequate and comfortable to outpatient. The aim in this study was to evaluate if the patients are satisfying with our lab services and to improve the services.

Methods

The standardized survey was distributed among adult and pediatric outpatients at three different hospitals within the king Abdulaziz Medical City (KAMC), Riyadh, SA during the second quarter (Q2) and third quarter (Q3) of 2023. The main five elements in survey were convenience of laboratory service hours, waiting time, comfort level, privacy, professionalism and curtsey. The established internal target was selected at greater than 80%Some of the answers by patients were extended to reflect the whole outpatient services and not limited to only the phlebotomy service although the survey structure has specified the laboratory area. In addition, some of the handwritten of the answers was not easy to read or understand them. Therefore, these answers have been excluded from the survey. Few steps have been taking to improve the services such as extending the services hours, reduction in the waiting time, improving the skills of the staff, improving comfort and environment.

Results

A total of 773 and 842 patients participated in the survey during Q2 and Q3 of 2023 respectively. An overall patient satisfaction rate was found to be 63.3% and 81% for Q2 and Q3 of 2023 respectively (p=0.025). The highest average of overall patient satisfaction rate was found to be at 94% for adult during Q3 compared to 53% at Q2 (p<0.001). The lowest overall patient satisfaction rate was found to be 69% for pediatrics’ patients for Q3 compared to 73% for Q2 (p=0.4252). In addition, 98 % of the surveyed patient have stated that they would highly recommend the out-patient phlebotomy service at KAMC for other patients. The waiting time displayed lower satisfaction rate (63 %) while privacy feature has shown the highest satisfaction rate 80%

Conclusions

Increasing of patient’s satisfaction rate has been achieved at the third quarter of the year and after implanting educational and training procedures.
A-202 Quality control design survey reveals 399 ways to do it wrong
Authors: Brooks Z
Published: October 2024

Background

The effectiveness of statistical quality control processes to detect unacceptable patient risk depends on the choices that laboratory professionals make for the design of quality control charts and acceptable patient risk.

Recommended best practice consists of putting a meaningful recent mean and SD on the QC chart, selecting rules based on the method’s margin for error to unacceptable risk or Sigma value, and basing acceptable risk on clinical need.

Methods

A survey was circulated through LinkedIn and Labvine. Forty respondents who included their credentials were included in the final analysis. Respondents were asked to select the one most correct answer four questions regarding the parameters that govern the effectiveness of quality control processes. 1. The best source of the mean on the QC chart? (Four choices) 2. Best source of the SD on the QC chart? (Five choices) 3. Best way to select QC rules for each QC sample? (Six choices) 4. If an analytical process “fails,” we should stop reporting before [errors are reported.] (Five choices)

A total of 400 potential patterns of QC selections were chosen. (4 * 5 * 5 * 4).

Results

When asked acceptable error rate if an analytical process “fails,” responses were More than 5% errors are reported - 11%. Any errors are reported - 66% It varies with clinical use of the test - 16% It varies with capabilities of our method - 8%

While most respondents chose at least one of the recommended answers for QC chart design and rules, only three chose the best choice for all parameters.

Conclusions

Despite decades of recommendations of best practice for quality control, typical practice throughout the laboratory community in general does not reflect this.

It is time to consider a new approach to teaching, validating and certifying competency in medical laboratory quality control.
A-208 Price Transparency of Laboratory Tests Across all Licensed Hospitals in Tennessee
Authors: Hart S A , Khan A , Booth G S , Wiencek J R
Published: October 2024

Background

The Hospital Price Transparency Final Rule federally mandates hospitals to provide gross price, discounted cash, payer-specific negotiated charges, and de-identified minimum and maximum negotiated rates within a machine-readable file and user-friendly display of shoppable services. Since implementation, compliance has been low and price variability has continued.

Methods

To assess hospital compliance, barriers to pricing information, and price variability in Tennessee, all hospitals websites were queried for gross, cash, and Blue Cross Blue Shield (BCBS) prices for 8 high-frequency laboratory tests in both mandated pricing sources. Barriers including click counts, data availability, and intra-hospital price discrepancies were noted.

Results

Only 2.8% of the 145 hospitals were compliant with federal law. Sub-analyses of the available machine-readable files, price estimators, and shoppable services files, only 50.4%, 4.9%, and 21.4% were found to be compliant, respectively. Barriers to pricing information included requiring protected health information (55.9%), missing at least 1 pricing source (7.6%), having no pricing sources available (6.2%), and involving more than 3 clicks to access cash price in machine-readable files (54.1%) and price estimators (68.6%.) The median total number of clicks from homepage to cash price in the machine-readable file and price estimator was 4 (range: 1-7) and 10.5 (range: 6-15), respectively. Average intra-hospital discrepancy for Basic Metabolic Panel cash prices across pricing sources was $101.30 (range: $0-1012.40). Price variability across Tennessee is shown in Figure 1. Maximum to minimum price multiples ranged from 29 to 114 for gross price, 57 to 243 for cash price, and 25 to 115 for BCBS price indicating price variability. Gross and cash prices were affected by median household income of the hospital’s county.

Conclusions

Our study shows low compliance with price transparency mandates, inequitable pricing affected by median household income, inconsistent and inaccessible pricing, and continued price variability in Tennessee.
A-252 Evaluation of the Use of One-tube Blood Collection and Automated Specimen Processing System for LIAISON® QuantiFERON®-TB Gold Plus Testing at a Large Regional Reference Laboratory
Authors: Cortez R , Perdido M , Muyrong M , Eberhard A , Melake S , Van T
Published: October 2024

Background

LIAISON® QuantiFERON®-TB Gold Plus (QFT-Plus) is an in vitro diagnostic assay for the indirect detection of infection caused by Mycobacterium tuberculosis complex (MTBC). QFT-Plus testing consists of four tubes (controls and TB antigens) and detects interferon-γ (IFN-γ) released by host cells when exposed to MTBC peptide antigens using chemiluminescence immunoassay (CIA) technology. Patient’s blood can be collected directly into four QFT-Plus tubes or into a single lithium heparin tube. If the one-tube collection process is utilized, blood must be aliquoted into each of the four QFT-Plus tubes prior to testing. In this study, we evaluated the workflow and feasibility of lithium-heparin blood collection and pre-analytical processing using the Copan Universe system for QFT-Plus testing on the LIAISON XL analyzer.

Methods

Whole blood collected into a 6 mL lithium heparin tube was mixed using a tube rotator prior to processing on the Copan UniVerse, which aliquots 0.9 mL blood into each of four QFT-Plus tubes and label the tubes with patient information. The lithium heparin tube is mixed again immediately prior to aliquoting into each QFT-Plus tube. Different methods of mixing (vortexing vs pipetting) were assessed for efficiency and performance. Walkaway feasibility was also assessed by testing aliquoting efficiency when loading 6, 9, 12 and 18 blood samples at a time. Visual inspection of the QFT-Plus tubes to check accuracy of labels was performed prior to incubation and validation of readability of the barcode labels through the analyzer was performed.

Results

Of 44 blood samples that were pipet mixed, 26 (59.1%), 15 (34.1%) and 3 (6.8%) showed no, slight and moderate hemolysis, respectively. None were grossly hemolyzed. Vortex mixing showed similar results with 61.3% (19/31) and 38.7% (12/31) showed no or slight hemolysis. However, bubble formation, which may interfere with pipetting by the UniVerse, was observed in several tubes when the samples were vortex mixed. The UniVerse appropriately aliquoted 0.9 mL blood and labeled 280 tubes. Only 1 (0.4%) tube had <0.9 mL volume detected. It takes about 20 minutes to aliquot 12 patient samples into four QFT-Plus tubes. Walkaway was possible when loading 18 patients’ samples at a time without negative downstream impact on pipetting or appropriate mixing of samples for QFT-Plus testing. All QFT-Plus tubes were labeled accurately with barcodes and accession numbers which were all read and processed through the analyzer.

Conclusions

Implementation of lithium-heparin blood collection for centralized QFT-Plus testing was feasible when used in conjunction with the Copan UniVerse, which allowed for high throughput specimen processing and mitigated the risk of sample mislabeling.
A-261 Outcome of a survey on dengue lateral flow immunoassay test kit reading and interpretation by medical laboratory staff in a hospital laboratory
Authors: Cheng K , Yeow J , Heng P , Wee G , Wong M , Teo B
Published: October 2024

Background

Lateral flow immunoassay (LFIA) tests, first introduced in 1959, are now the mainstay of clinical laboratories. Khoo Teck Puat Hospital (KTPH) is a 795-bed acute care general hospital located in the north of Singapore. The Department of Laboratory Medicine has been using dengue LFIA test kits for the detection of dengue NS1 antigen, IgM antibodies and IgG antibodies. While kits are cost-effective, user-friendly and provide rapid results, there is subjectivity in reading and interpretation of results.

Methods

We conducted a survey to assess test reading and interpretation by medical laboratory staff. Six serum and plasma specimens were analysed using Bioline™ Dengue IgG/IgM WB test device. Test kits at the end-point of sample incubation were photographed in both well-lit and dim conditions. A survey questionnaire was prepared using an online form builder tool using the photographs. Staff were invited to participate in the survey. They were allowed to report the result as ‘Positive’, ‘Negative’ or ‘Equivocal’.

Results

A total of sixteen responses were received. Results were 100% concordant for all 6 specimens in both well-lit and dim conditions. For one case, under a well-lit condition, 15 staff reported the result as ‘Positive’ while one staff reported ‘Equivocal’. Most of the reported results for samples with no consensus is split between ‘Positive’ and ‘Equivocal’.

Conclusions

Dengue viruses of all 4 known serotypes are endemic in Singapore. Positive results are tracked on a national level to identify areas of high dengue infection for intensive environmental and vector control measures. Hence, accurate reporting and identification of patients with dengue infection is important. Our survey shows that lighting conditions do not affect the interpretation of LFIA results. Reading and interpretation of dengue LFIA test kits however, remain dependent on user interpretation and newer test kits with optical readers may be useful in mitigating this.
A-272 Evaluation of a Real-Time Multiplex Polymerase Chain Reaction Assay for Simultaneous Detection of Respiratory Pathogens in Nasopharyngeal Specimens
Authors: Alturkmani R , Southard D , Branson L , Jaime A , Katrangi W
Published: October 2024

Background

Respiratory infections present a significant challenge due to the diverse range of pathogens involved and the possibility of concurrent infections, emphasizing the importance of rapid and accurate detection for effective treatment. Advancements in molecular methods have provided cost-effective and reliable solutions for the identification of respiratory pathogens. In this study, we aimed to assess performance characteristics of the Seegene Allplex™ 2019-nCoV Assay and Seegene Novaplex™ Respiratory Panel Assays for simultaneous amplification and detection of 22 respiratory pathogens using real-time multiplex polymerase chain reaction (PCR).

Methods

Nucleic acid extraction was performed using the MagMAX™ Viral/Pathogen Nucleic Acid Isolation Kit (Thermo Fisher Scientific, MA) on the CyBio® FeliX liquid handler (Analytik Jena, Germany). PCR amplification and detection were performed using the Seegene Novaplex™ Respiratory Panels 1A, 2, 3, PneumoBacter Assay, and Allplex™ 2019-nCoV Assay (Seegene Inc, South Korea) on the CFX96™ System (Bio-Rad Laboratories, CA). The assays utilize Seegene MuDT™ technology that allows for the detection of multiple targets in a single channel without the need for melt curve analysis. For method validation, precision studies were performed within-run and over 4 days. The limit of detection was verified by using plasmids from Seegene containing the target sequence for each pathogen at known concentrations. Method comparison studies were carried out by extracting and analyzing a range of 41 to 79 split samples for each pathogen against the BioFire® Respiratory 2.1 Panel (bioMérieux, France), cobas® Influenza A/B & RSV Assay on the cobas® liat system (Roche Diagnostics, IN), and Lyra® SARS-CoV-2 Assay (Quidel, CA) on the CFX96™ system. Additional accuracy studies were performed by spiking negative patient samples with standards from ZeptoMetrix® (Antylia Scientific, IL) containing known concentrations of the targeted respiratory pathogens.

Results

Precision studies demonstrated consistent and reproducible results for all pathogens. The limit of detection was verified at 1000 copies/reaction for human parainfluenza virus 4 and human metapneumovirus, and at 100 copies/reaction for all other pathogens. Results of the spike-and-recovery studies were consistent with expected results for all targets. Patient correlation studies showed 100% agreement with expected pathogen identification for 19 pathogens, and greater than 97.9% agreement for influenza B virus, respiratory syncytial virus, human parainfluenza virus 4, and human coronavirus 229E.

Conclusions

The Seegene Allplex™ 2019-nCoV Assay and Novaplex™ Respiratory Panel Assays offer a rapid and reliable method for detecting respiratory pathogens in nasopharyngeal specimens. The capability of the assays to detect multiple targets in a single well enhances efficiency, cost-effectiveness, and turnaround time.
A-274 The Yield of the Limulus Amebocyte Lysate (LAL), Which is Used for Endotoxin Detection and Fungal Diagnosis is Increased by Caffeine Collection Buffer
Authors: Zhang S , Zhang M , Zhang J
Published: October 2024

Background

Limulus Amebocyte Lysate (LAL), which is a major component of Fungal infection diagnosis kit, is used for the adjunct diagnosis of invasive fungal infection. This study used different blood collection buffers to find the optimal blood collection buffer to maximize the yield of LAL. The PBS collection buffer was found to prevent degranulation during blood collection procedure and the PBS-derived Limulus Amebocyte Lysate (LAL) was observed to work in both the chromogenic test and the turbidimetric method assays. A similar phenomenon was observed with the caffeine collection buffer.

Methods

To further confirm this observation, we used a caffeine collection buffer to collect the blood of horseshoe crabs in the 2023 bleeding season (from July to October). Once a week, 3 crabs were bled for a total of 30 crabs. The blood of each crab was collected using the caffeine collection buffer and the 3% NaCl collection buffer, respectively. The cell pellets were resuspended into LAL reagent water (LRW) or 5 mM CaCl2. The final LAL activity was tested by both chromogenic and turbidimetric assay methods.

Results

The results showed that a caffeine collection buffer could prevent degranulation for over 1 hr and the activity yield of caffeine-derived LAL is much higher than that of the 3% NaCl solution. There was no discernible impact upon activity yield of crab size, period of the bleed season, or the vendors. Interestingly, caffeine-derived LAL was observed to work in both the chromogenic and turbidimetric assays. The enzyme characteristic of the LAL was also described.

Conclusions

Caffeine collection buffer prevents amebocyte degranulation during blood collection and processing. The activity of caffeine LAL is much higher than that of 3% NaCl. Caffeine LAL works in both chromogenic test and turbidimetric assay.
A-277 Viability of multi-drug resistant organisms in a fecal collection and transport system stored at ultra-low temperature
Authors: Cowden L , Kelly B J
Published: October 2024

Background

Epidemiological studies are constantly investigating new, easier ways to collect and store patient specimens that allow for flexible testing windows and long-term storage as well as accurate quantification of organisms of interest. The FecalSwabTM system (Copan, Brescia, Italy) is intended for the collection and preservation of rectal and fecal specimens. This system includes a preservation medium which serves to maintain the viability of enteric pathogens during transport to a clinical laboratory for up to 72 hours at 4oC. The objective of this study was to assess the continued viability of multi-drug resistant organisms (MDROs) suspended in the FecalSwab sample format when frozen at -80°C and the impact of freeze-thaw cycles.

Methods

A total of 40 organisms were chosen spanning methicillin-resistant Staphylococcus aureus (MRSA, n=10), carbapenem-resistant Pseudomonas aeruginosa (CRPA, n=5), carbapenem-resistant Enterobacterales (CRE, n=5), vancomycin-resistant Enterobacterales (VRE, n=10) and extended-spectrum beta-lactamase containing Enterobacterales (ESBL, n=10). Each organism was spiked into FecalSwab at standardized concentrations. At each time point, FecalSwab media was plated onto blood agar and colonies were quantified. Each of the 40 organisms were assessed one-week post-freeze and over the course of freeze-thaw cycles at days 3 and 5. The survival of each MDRO was evaluated by calculating a difference between the concentration of organisms recovered (CFU per 10uL media) at each time point and the concentration of organisms confirmed present at the time of inoculation. Percent recovery was calculated from this difference.

Results

One week after freezing, the percent recovery for MRSA, VRE, ESBL, CRE, and CRPA averaged to 102%, 201%, 17.8%, 7.6%, and 0.8%, respectively (Kruskal Wallis p < 0.001), with significant differences noted between gram positive and gram negative organisms (Kruskal Wallis p <0.001).

Conclusions

Epidemiological studies interested in MDRO surveillance rely on methodologies that allow for accurate quantification of viable organisms. In this study, we’ve evaluated the viability of several multi-drug resistant organisms when frozen at -80°C in the FecalSwab. The FecalSwab system is intended for the collection of rectal swab and fecal specimens and to preserve the viability of enteric pathogenic bacteria for testing in the clinical laboratory. Although it was not specifically designed to preserve MDROs, it performed well with MRSA and VRE, but less well with CRE, CRPA and ESBL organisms. When using the FecalSwab system, the observed gram-specific differences may inform the suitability of this system depending on the organism(s) of interest.
A-282 Purpura fulminans caused by Haemophilus influenzae: case report of unusual etiology
Authors: Levi J , Bandeira S P , Castelo M H , Cavalcante L L , Pereira M M , Amaral E S , Oliveira B L , Furtado G P , Ventura F M , Cury R C
Published: October 2024

Background

Fulminant purpura is a clinical syndrome characterized by a purplish, ischemic-looking skin rash, commonly accompanied by systemic symptoms ranging from acute febrile syndrome to septic shock. Due to high lethality of possible infectious etiologies, immediate recognition and early initiation of empirical antimicrobial therapy are crucial to ensure better outcomes. Interdisciplinary collaboration among healthcare teams, infectious disease specialists and microbiologists is essential to ensure accurate and early microbiological diagnosis.

Methods

This work aims to report a case of Haemophilus influenzae-induced purpura fulminans that occurred in Fortaleza-CE, a coastal city in northeastern Brazil, highlighting clinical recognition and microbiological identification, based on review of medical records.

Results

Case report A 59-year-old man, originally from Germany, was on vacation in Brazil. He presented to emergency medical service with an acute onset of fever, abdominal pain and diarrhea, progressing to decreased level of consciousness and purplish ischemic skin lesions with hemorrhagic bullae on trunk and extremities (Figure 1), with no history of trauma. Upon admission, the blood exams showed bicytopenia - 1900 leukocytes/µL (86% segmented) and 51,000 platelets/µL - and very high C-reactive protein (41.58 mg/dL). Although empirical antimicrobial therapy with vancomycin and piperacillin-tazobactam was initiated, patient progressed to septic shock, hepatic dysfunction, requiring mechanical ventilation, vasopressor support, and renal replacement therapy. Blood cultures from hospital admission were positive after about 14 hours and allowed isolation of small and translucent colonies in Chocolate PVX plate Agar (BioMerieux™). Maldi tof analysis by Vitek MS identified H. influenzae (99.9 % accuracy). Despite prolonged hospitalization due to multiple organ dysfunctions, patient had a positive outcome.

Conclusions

This case illustrates the importance of immediate recognition of the syndrome coupled with assertive empirical treatment and early microbiological diagnosis for a positive clinical outcome, even in a severe presentation. Multiprofessional approach is essential for accurate and early diagnosis.
A-324 Performance and Turnaround Time of Plasma Lactate Assay on POCT, Blood Gas Instrument, and Chemistry Analyzer
Authors: Lockart K , Jin M
Published: October 2024

Background

Time is a critical factor of plasma lactate testing in the management of patients with sepsis. To best serve these patients, we must optimize testing methods to provide a turnaround time (TAT) that guides efficient patient care. Point of care tests (POCTs) provide rapid results for emergency department and medical intensive care unit but are not feasible for all hospital settings. Laboratory testing methods on an automation line provide greater efficiency but result slowly due to need of specimen preparation and longer analytical time. The goal of this study is to provide detailed TATs of plasma lactate testing among the methods of POCT, chemistry analyzer in an automation line, and blood gas analyzer.

Methods

Plasma lactate testing was performed by three methods, GEM Premier ChemSTAT (POCT in ER only), Beckman AU5800 (chemistry analyzer), and Radiometer ABL800 (blood gas instrument). The TAT of lactate for each method was measured and include the time from specimen collection to laboratory receipt (except for POCT method), and time from specimen receipt to resulting (including specimen preparation for Beckman AU5800).

Results

The average TATs of lactate testing for each method in all hospital sites are detailed with respect to each event and subcategorized (Table 1). The average TAT of 12.0 min on Radiometer ABL800 is higher than the TAT of 2.5 on GEM Premier ChemSTAT method but is greatly reduced compared to the TAT of 35.4 min on Beckman AU5800.

Conclusions

Radiometer ABL800 method could be the optimal laboratory method for plasma lactate testing fulfilling the TAT (average 12 min), with less test cancellation due to specimen stability issue, and combines testing with blood gases. Using three Radiometer ABL800 instruments, we manage the performance of around 70 plasma lactate tests daily.
B-014 Performance evaluation of the automated cell image analyzer DI-60 for leukocyte differential count
Authors: Chang S , Kim E , Kim Y , Won D
Published: October 2024

Background

The Sysmex DI-60 system (Sysmex, kobe, Japan) is an automated cell image analyzer that captures cell images and analyzes them. The aim of this study was to evaluate the performance of DI-60 for leukocyte differential count in comparison with manual differential count or XN-20.

Methods

A total of 205 samples were analyzed. The agreement between DI-60 pre-classification and post-verification by medical technicians was determined. The correlation and ability to identify clinically important abnormal cells of DI-60 post-verification were evaluated.

Results

The overall agreement of DI-60 pre-classification was 84.7% (Table 1). The correlation between DI-60 post-verification and manual differential counts were exellent (r2 > 0.85) for neutrophil, lymphocyte, monocyte and eosinophil, but was very low for basophil (r2 = 0.3759). The correlation between DI-60 post-verification and leukocyte differential counts by XN-20 were exellent (r2 > 0.90) for neutrophil, lymphocyte and eosinophil. However, monocyte and basophil showed a relatively low correlation of r2 = 0.6343 and r2 = 0.3118, respectively but was very low for basophil (r2 0.3759). The ability of DI-60 post-verification to identify clinically important abnormal cells including blast, promyelocyte, myelocyte, metamyelocyte and NRBC demonstrated excellent efficiency (80.8 to 96.3%) except for NRBC (51.0%). Overall sensitivity was 63.7-88.2%, and specificity was 84.3-95.5% excluding NRBC (43.7%).

Conclusions

DI-60 showed excellent pre-classification and generally high correlation compared to manual leukocyte differential counts. Although additional verification with PBS review by experienced medical technician may still be required, the performance DI-60 makes it an efficient screening tool in clinical laboratories.
B-054 Performance Evaluation of the VITROS HIV Combo Assay on the Ortho VITROS 3600 system
Authors: cao x , Zhang B
Published: October 2024

Background

n 2014, the US CDC updated HIV screening algorithm, recommended any assay capable of reliably detecting p24 antigen and both IgG&IgM antibodies as starting point. In 2021 Chinese FDA approved VITROS HIV Combo assay as early detection of acute HIV infection with fourth-generation Ag/Ab combination test, with several declared earlier seroconversion panel reactivity than the third generation assay. This study records the experiment run to assess clinical performance using prospectively collected HIV-1 and HIV-2 antibody positive samples from Chinese CDC on the VITROS HIV Combo Assay on the VITROS 5600 Integrated System,

Methods

In total 450 serum/plasma samples, including 164 HIV antibody positive (162 HIV-1 antibody positive and 2 HIV-2 antibody positive) and 286 HIV negative. The HIV-2 antibody positive samples were purchased from Seracare (United States), and the remaining samples were prepared by the Chinese CDC reference laboratory. In the samples prepared in the reference laboratory, all HIV-1 antibody positive samples were tested by HIV antibody confirmation test, and the result was positive; The HIV negative samples were confirmed based on a comprehensive assessment of HIV antibodies, HIV-1 p24 antigen, HIV nucleic acid testing, and follow-up testing results, and window period has been ruled out. Ten linear and sensitivity reference samples were added to the HIV-1 p24 antigen national reference material (batch number 20190505, purchased from the China Academy of Food and Drug Control) . The antigen concentrations from L1 to L10 were 20, 10, 5, 2.5, 1.25, 0.625, 0.313, 0.156, 0.0781, and 0 IU/ml, respectively.

Results

The sensitivity for this positive population of samples in the VITROS Combo test was calculated as 100.00% (164/164) with an exact 95% confidence interval (Cl) of 99.26% to 100.00%. The specificity for this negative population was 99.58% (Cl 99.38%-99.73%).

Conclusions

The sensitivity and specificity of VITROS Combo assay are very high. With class leading antigen sensitivity doesn’t sacrifice specificity. This new assay delivers excellent confidence in results, and with more target (HIV-1 p24) being detected, can helps laboratory shortening HIV infection window, improve operators and technicians’ confidence in the outcome of HIV testing.
B-056 Clinical and Analytical Performance Evaluation of Two Immunoassays for the Detection of Mite Specific Serum IgE for Allergy Diagnosis
Authors: Ozaki B C , Aarestrup P F , Cheloni E C , Aarestrup M F , Aarestrup B V , Aarestrup F M
Published: October 2024

Background

IgE-mediated allergic diseases can be considered a modern epidemic, with exponential growth mainly in industrialized countries. Diagnosis is usually based on detailed medical history, physical examination, skin or challenge test and the determination of allergen-specific serum IgE - a laboratory test that has become a high-value tool in the allergy patient's journey over the last three decades. As the identification of specific immunoglobulin E (sIgE) for a given allergen is important to aid in the allergy diagnosis, several methods for detecting IgE in vitro are available worldwide and, in recent years, there have been several improvements in laboratory methodologies bringing greater advances in terms of clinical and analytical performance. The study aims to evaluate the clinical performance and correlation between two different sIgE assays (IMMULITE® 2000 3gAllergy™ and ImmunoCAP) and their concordance with Skin Prick Test (SPT) and clinical history.

Methods

This prospective study was conducted with approximately 130 consecutive patients who underwent evaluation of allergic diseases in different centers in Brazil. Clinical data, blood samples, and SPT results were collected. With the blood samples, the allergens D1, D2 and D201 were evaluated using both methods (IMMULITE® 2000 3gAllergy™ and ImmunoCAP) and the data were evaluated in a correlation study and clinical concordance analysis.

Results

Qualitatively evaluating the sIgE results between the two immunoassays, at the cutoff point considered clinically significant (≥ 0.35 KU/L), a total agreement of 95.2% (D1); 95.1% (D2), 91.7% (D201) and 96.8% (Derp2) was observed. Semi-quantitatively evaluating through reactive interpretation, an agreement of 89.5% (D1); 91.06% (D2); 87.60% (D201) and 93.33% (Derp2) was observed. Spearman's correlation between the analytical methods was 0.85 (D1), 0.93 (D2), 0.68 (D201) and 0.76 (Derp2). When compared with the SPT results, a total agreement of 78.7% and 80.1% was obtained for 3gAllergy and ImmunoCAP, respectively, with slightly higher positive agreement for both methods.

Conclusions

The two methods have good agreement with each other, with greater differences when evaluated quantitatively. However, when compared to clinical history and skin prick test results, both perform very similarly with a few differences that may be caused by the difference in the assay design.
B-078 Serodiagnosis of Rheumatoid Arthritis Using the New Accentis Chemiluminescence Immunoassay Platform for Anti-CCP Antibody Detection
Authors: Weiss J , Elleuche S , Saschenbrecker S , Dähnrich C
Published: October 2024

Background

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases and the most frequent chronic inflammatory arthropathy. Reliable diagnosis at the earliest possible stage is indispensable to keep the disease under control with suitable therapy and to prevent irreversible joint damage. Autoantibodies against cyclic citrullinated peptides (CCP) are a highly specific marker for RA with relevance for (differential) diagnosis, prediction and prognosis. In this study, we investigated the clinical and analytical performance of a newly developed anti-CCP chemiluminescence immunoassay (ChLIA) system.

Methods

Serum samples from 170 patients with clinically confirmed RA and from a control panel of 274 patients with other diseases were analyzed using the EUROIMMUN Anti-CCP ChLIA (IgG), which was processed on the fully automated random-access system Accentis (EUROIMMUN). The results were compared with those obtained with the EUROIMMUN Anti-CCP ELISA (IgG) with regard to sensitivity, specificity and inter-assay concordance.

Results

The ChLIA achieved a sensitivity of 71.2% (121/170) and a specificity of 97.4% (267/274), while the ELISA was less sensitive (67.5%, 114/170) and specific (96.4%, 264/274). The qualitative results showed positive and negative agreement rates between the two assays of 92.7% (115/124) and 95.9% (307/320), respectively, resulting in 95.0% (422/444) overall agreement and a kappa score (0.878) indicating near perfect agreement.

Conclusions

The new Accentis ChLIA showed improved sensitivity and specificity for the detection of anti-CCP antibodies compared to the corresponding ELISA. Given the enhanced clinical performance and the practical benefits of using a random-access system, this ChLIA platform can effectively support the diagnosis of RA.
B-098 Clinical comparison of five assays for the detection of anti-dsdna antibodies and their correlation with complement consumption
Authors: Ricchiuti V , Obney J R , Holloway B , Aure M , Mahler M
Published: October 2024

Background

Anti-dsDNA antibodies are highly specific and part of the classification criteria for systemic lupus erythematosus (SLE). They correlate with disease activity and contribute to the pathogenesis of lupus nephritis (LN). This study aimed to compare five methods for anti-dsDNA antibody detection and to estimate their association with complement consumption.

Methods

186 samples were collected at Labcorp and tested on five assays: Crithidia luciliae indirect immunofluorescence test (CLIFT, Euroimmun, Lübeck Germany), BioPlex 2200 dsDNA (BioRad, Hercules, US), QUANTA Lite HA dsDNA ELISA, QUANTA Flash dsDNA chemiluminescent immunoassay (CIA), and Aptiva dsDNA, a particle-based multi-analyte technology (PMAT) immunoassay (all 3 assays, Inova Diagnostics, USA). Complement C3 and C4, measured with Cobas c 502 (Roche Diagnostics, USA), were used as serological surrogates and compared to each assay to assess the correlation with disease activity.

Results

The quantitative agreement varied between 0.60 (BioPlex vs. CLIFT) and 0.96 (Aptiva vs. QUANTA Flash) (Table 1). The C3 agreement from highest to lowest was: HA dsDNA ELISA, CLIFT, QUANTA Flash, Aptiva, then BioPlex 2200. The findings were compared to qualitative results derived from CLIFT testing, since CLIFT is often used as the confirmation assay for anti-dsDNA. The highest area under the curve (AUC) from the receiver operating characteristic (ROC) curve was found for QUANTA Flash (0.95) followed by Aptiva and HA ELISA (both 0.94) and then BioPlex (0.87).

Conclusions

Anti-dsDNA antibodies measured using different methods showed varying agreement with CLIFT and complement consumption. Aptiva and QUANTA Flash dsDNA were highly correlated and in strong concordance with low C3 levels.
B-114 Reference interval (RI) estimation for TSH in adults using an indirect method with unsupervised machine learning tool and R programming language
Authors: Meira Dias C , Correa Wengerkievicz Lopes A , Grando Remor Canali D , Falci Vieira L M , de Souza Santos B , Goetz Muller K , de Oliveira Weingrill Sabino C
Published: October 2024

Background

Thyroid-stimulating hormone (TSH) plays a fundamental role in regulating thyroid hormones T3 (triiodothyronine) and T4 (thyroxine). Understanding TSH test results is essential for effective management of thyroid disorders and depends, among other factors, on establishing specific reference intervals (RI) for the population being served. We aimed to estimate the reference intervals for TSH in the adult population served by a large diagnostic network in Brazil.

Methods

We employed data mining followed by estimation using an indirect method through the LabRI™ algorithm with parametric, non-parametric, and robust statistical treatments for outlier exclusion, a series of algorithms programmed in R Language. Included were TSH values from outpatients, aged 20 to 60 years, both sexes, from two analytical platforms. Used as a comparative RI recommended by the American Thyroid Association (ATA, 2014). Data were extracted from the Data Lake, from January to December 2022, from two laboratories in Brazil. Exclusion criteria: samples from hospital sources and referral laboratories; pregnant; some laboratory tests correlated with de TSH test; samples from patients using thyroid hormone and medications that may interfere with hormonal function and TSH laboratory analysis.

Results

After exclusion criteria, the sample totaled 26,909 adults of both sexes. After excluding 2.24% outliers, the estimated RI was 0.67-4.26 mIU/L, with the comparative RI chosen for this study being the one recommended by ATA of 0.40-4.00 mIU/L. The RI obtained in our study was similar to the Canadian RI harmonization study for TSH (0.60-4.48 mIU/L).

Conclusions

We estimated the RI, harmonized between Roche and Siemens platforms, to be 0.67-4.26 mIU/L. The RI obtained by the LabRI™ tool is equivalent to the Adeli study (2023) and is under discussion by the company's endocrinology committee for whether to use the estimated RI from our internal study or the one recommended by ATA (2014) in reports.