Antibody Detection and Dynamic Characteristics in Patients With Coronavirus Disease 2019

Abstract Background The coronavirus disease 2019 (COVID-19), caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been rapidly spreading nationwide and abroad. A serologic test to identify antibody dynamics and response to SARS-CoV-2 was developed. Methods The antibodies against SARS-CoV-2 were detected by an enzyme-linked immunosorbent assay based on the recombinant nucleocapsid protein of SARS-CoV-2 in patients with confirmed or suspected COVID-19 at 3–40 days after symptom onset. The gold standard for COVID-19 diagnosis was nucleic acid testing for SARS-CoV-2 by real-time reverse-transcription polymerase chain reaction (rRT-PCR). The serodiagnostic power of the specific immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against SARS-CoV-2 was investigated in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and consistency rate. Results The seroconversion of specific IgM and IgG antibodies were observed as early as the fourth day after symptom onset. In the patients with confirmed COVID-19, sensitivity, specificity, PPV, NPV, and consistency rate of IgM were 77.3% (51/66), 100%, 100%, 80.0%, and 88.1%, respectively, and those of IgG were 83.3% (55/66), 95.0%, 94.8%, 83.8%, and 88.9%. In patients with suspected COVID-19, sensitivity, specificity, PPV, NPV, and consistency rate of IgM were 87.5% (21/24), 100%, 100%, 95.2%, and 96.4%, respectively, and those of IgG were 70.8% (17/24), 96.6%, 85.0%, 89.1%, and 88.1%. Both antibodies performed well in serodiagnosis for COVID-19 and rely on great specificity. Conclusions The antibodies against SARS-CoV-2 can be detected in the middle and later stages of the illness. Antibody detection may play an important role in the diagnosis of COVID-19 as a complementary approach to viral nucleic acid assays.

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Highlighted Prospects of an IgM/IgG Antibodies Test in Identifying Individuals With Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection

Archives of Pathology & Laboratory Medicine ◽

10.5858/arpa.2020-0310-sa ◽

2020 ◽

Vol 145 (1) ◽

pp. 39-45

Author(s):

Yaqing Li ◽

Qiang He ◽

Rizhen Yu ◽

Hui Jiang ◽

Weizhong Wang ◽

...

Keyword(s):

Nucleic Acid ◽

Severe Acute Respiratory Syndrome ◽

Ct Scanning ◽

Immunoglobulin M ◽

Antibody Detection ◽

Igg Antibodies ◽

Igg Antibody ◽

Imaging Results ◽

Close Contacts ◽

Nucleic Acid Tests

Context.— Covert severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections could be seeding new outbreaks. How to identify asymptomatic SARS-CoV-2 infections early has become a global focus. Objective.— To explore the roles of immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies detection, nucleic acid tests, and computed tomography (CT) scanning to identify asymptomatic SARS-CoV-2 infection. Design.— The clinical data of 389 individuals with close contacts, including in general characteristics, SARS-CoV-2 etiology, serum-specific IgM and IgG antibody detection and CT imaging results, were systematically analyzed. Results.— The present study showed that only 89 of 389 individuals with close contacts were positive after the first nucleic acid test, while 300 individuals were still negative after 2 nucleic acid tests. Among the 300 individuals, 75 did not have pneumonia, and the other 225 individuals had pulmonary imaging changes. A total of 143 individuals were eventually diagnosed as having asymptomatic infection through IgM antibody and IgG antibody detection. The sensitivity, specificity, and false-negative rate of IgM and IgG antibody detection were approximately 97.1% (347 of 357), 95.3% (204 of 214), and 4.67% (10 of 214), respectively. It also indicated that during approximately 2 weeks, most individuals were both IgM positive and IgG positive, accounting for 68.57% (72 of 105). During approximately 3 weeks, the proportion of IgM-positive and IgG-positive individuals decreased to 8.57% (9 of 105), and the proportion of IgM-negative and IgG-positive individuals increased to 76.19% (80 of 105). Conclusions.— There are highlighted prospects of IgM/IgG antibody detection as a preferred method in identifying the individuals with asymptomatic SARS-CoV-2 infection, especially combined with nucleic acid tests and pulmonary CT scanning.

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Recombinant Protein-Based Enzyme-Linked Immunosorbent Assay and Immunochromatographic Tests for Detection of Immunoglobulin G Antibodies to Severe Acute Respiratory Syndrome (SARS) Coronavirus in SARS Patients

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.11.2.287-291.2004 ◽

2004 ◽

Vol 11 (2) ◽

pp. 287-291 ◽

Cited By ~ 38

Author(s):

Ming Guan ◽

Hsiao Ying Chen ◽

Shen Yun Foo ◽

Yee-Joo Tan ◽

Phuay-Yee Goh ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Recombinant Proteins ◽

Immunosorbent Assay ◽

Immunoglobulin G ◽

Predictive Value ◽

Rapid Test ◽

Enzyme Linked Immunosorbent Assay ◽

Igg Antibodies ◽

Kappa Value ◽

Sensitivity Specificity

ABSTRACT An enzyme-linked immunosorbent assay (ELISA) and a rapid immunochromatographic test for detection of immunoglobulin G (IgG) antibodies in severe acute respiratory syndrome (SARS) patients were developed by utilizing the well-characterized recombinant proteins Gst-N and Gst-U274. The ELISA detected IgG antibodies to SARS-CoV in all 74 convalescent-phase samples from SARS patients while weakly cross-reacting to only 1 of the 210 control sera from healthy donors. This finding thus led to a kit sensitivity, specificity, and accuracy of 100, 99.5, and 99.6%, respectively. The test thus provided a positive predictive value (PPV) of 98.7% and a negative predictive value (NPV) of 100%. In addition, the ELISA gave a positive delta of 5.4 and a negative delta of 3.6, indicating an excellent differentiation between positives and negatives. The same recombinant proteins were also applied to a newly developed platform for the development of a 15-min rapid test. The resulting rapid test has an excellent agreement of 99.6%, with a kappa value of 1.00, with the ELISA. Again, this rapid test was able to detect 100% of the samples tested (n = 42) while maintaining a specificity of 99.0% (n = 210). The PPV and NPV for the rapid test thus reached 95.3 and 100%, respectively.

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Diagnosis of Dengue Virus Infection by Detection of Specific Immunoglobulin M (IgM) and IgA Antibodies in Serum and Saliva

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.10.2.317-322.2003 ◽

2003 ◽

Vol 10 (2) ◽

pp. 317-322 ◽

Cited By ~ 83

Author(s):

Angel Balmaseda ◽

María G. Guzmán ◽

Samantha Hammond ◽

Guillermo Robleto ◽

Carolina Flores ◽

...

Keyword(s):

Dengue Virus ◽

Immunoglobulin M ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Control Group ◽

Serum Samples ◽

Diagnostic Modality ◽

Iga Antibodies ◽

Specific Immunoglobulin ◽

Feasible Alternative

ABSTRACT To evaluate alternative approaches to the serological diagnosis of dengue virus (DEN) infection, the detection of DEN-specific immunoglobulin M (IgM) and IgA antibodies in serum and saliva specimens was assessed in 147 patients with symptoms of DEN infection seen at the Ministry of Health in Nicaragua. Seventy-two serum samples were determined to be positive for anti-DEN antibodies by IgM capture enzyme-linked immunosorbent assay, the routine diagnostic procedure. Serum and saliva specimens were obtained from 50 healthy adults as additional controls. IgM was detected in the saliva of 65 of the 72 serum IgM-positive cases, 6 of the 75 serum IgM-negative cases, and none of the control group, resulting in a sensitivity of 90.3% and a specificity of 92.0% and demonstrating that salivary IgM is a useful diagnostic marker for DEN infection. Detection of IgA in serum may be another feasible alternative for the diagnosis of DEN infection, with serum IgA found in 68 (94.4%) of the IgM-positive cases. In contrast, detection of IgA in saliva was not found to be a useful tool for DEN diagnosis in the present study. Further studies of the kinetics of antibody detection in another set of 151 paired acute- and convalescent-phase serum samples showed that DEN-specific IgA antibodies were detected in more acute-phase samples than were IgM antibodies. Thus, we conclude that DEN-specific IgA in serum is a potential diagnostic target. Furthermore, given that saliva is a readily obtainable, noninvasive specimen, detection of DEN-specific salivary IgM should be considered a useful, cheaper diagnostic modality with similar sensitivity and specificity to IgM detection in serum.

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Detection and Titration of Human Herpesvirus-8–Specific Antibodies in Sera From Blood Donors, Acquired Immunodeficiency Syndrome Patients, and Kaposi's Sarcoma Patients Using a Whole Virus Enzyme-Linked Immunosorbent Assay

Blood ◽

10.1182/blood.v92.1.53.413k30_53_58 ◽

1998 ◽

Vol 92 (1) ◽

pp. 53-58 ◽

Cited By ~ 98

Author(s):

Louise G. Chatlynne ◽

William Lapps ◽

Michael Handy ◽

Yao Q. Huang ◽

Rizwan Masood ◽

...

Keyword(s):

Immunosorbent Assay ◽

Kaposi's Sarcoma ◽

Blood Donors ◽

Human Herpesvirus ◽

Kaposi’S Sarcoma ◽

Antibody Detection ◽

Human Herpesvirus 8 ◽

Enzyme Linked Immunosorbent Assay ◽

Igg Antibodies ◽

Herpesvirus 8

A human herpesvirus-8 (HHV-8) enzyme-linked immunosorbent assay (ELISA) with a whole virus lysate as antigen was developed and used to measure the seroprevalence rate and levels of IgG antibodies to HHV-8 in sera/plasma of various patient groups and blood donors. The virus antigen was prepared from the KS-1 cell line, which produces lytic virus, and therefore contains a broad array of viral proteins. Seroprevalence studies using this ELISA showed the following: 10 of 91 blood donors (11%) had an average HHV-8 antibody titer of 118; 67 of 72 (93%) classic Kaposi's sarcoma (KS) patients were positive with an average titer of 14,111; and 57 of 62 (92%) KS/human immunodeficiency virus (HIV) patients were positive with an average titer of 4,000. A study on a very limited number of serial serum samples from patients before and after diagnosis with KS showed highly elevated antibody titers to HHV-8 virus after KS lesions developed. Preliminary data show that 50% of the sera from HIV-1+ homosexual patients contain IgG antibodies to HHV-8 suggesting that this population is at high risk for developing KS. Antibody results correlated well with the confirmatory immunofluorescent assays (IFA) using KS-1 cells as the substrate. This HHV-8 IgG antibody detection ELISA is sensitive and specific and does not cross-react with Epstein-Barr virus (EBV) or other human herpesviruses. The results of this HHV-8 antibody survey suggest that this rapid ELISA assay can be used to screen large numbers of sera to find those at risk for developing KS.

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Comparison of an IgG-Specific Enzyme-Linked Immunosorbent Assay Cutoff of 0.4 Versus 0.8 and 1.0 Optical Density Units for Heparin-Induced Thrombocytopenia

Clinical and Applied Thrombosis/Hemostasis ◽

10.1177/1076029615606532 ◽

2016 ◽

Vol 23 (3) ◽

pp. 282-286 ◽

Cited By ~ 5

Author(s):

Brianne M. Ritchie ◽

Jean M. Connors ◽

Katelyn W. Sylvester

Keyword(s):

Optical Density ◽

Immunosorbent Assay ◽

Predictive Value ◽

Retrospective Chart Review ◽

Serotonin Release ◽

Enzyme Linked Immunosorbent Assay ◽

Platelet Factor ◽

Heparin Induced Thrombocytopenia ◽

Institutional Review ◽

Sensitivity Specificity

Background: Previous studies have demonstrated optimized diagnostic accuracy in utilizing higher antiheparin–platelet factor 4 (PF4) enzyme-linked immunosorbent assay (ELISA) optical density (OD) thresholds for diagnosing heparin-induced thrombocytopenia (HIT). We describe the incidence of positive serotonin release assay (SRA) results, as well as performance characteristics, for antiheparin–PF4 ELISA thresholds ≥0.4, ≥0.8, and ≥1.0 OD units in the diagnosis of HIT at our institution. Methods: Following institutional review board approval, we conducted a single-center retrospective chart review on adult inpatients with a differential diagnosis of HIT evaluated by both antiheparin–PF4 ELISA and SRA from 2012 to 2014. The major endpoints were to assess incidence of positive SRA results, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy at antiheparin–PF4 ELISA values ≥0.4 OD units when compared to values ≥0.8 and ≥1.0 OD units. Clinical characteristics, including demographics, laboratory values, clinical and safety outcomes, length of stay, and mortality, were collected. Results: A total of 140 patients with 140 antiheparin–PF4 ELISA and SRA values were evaluated, of which 23 patients were SRA positive (16.4%) and 117 patients were SRA negative (83.6%). We identified a sensitivity of 91.3% versus 82.6% and 73.9%, specificity of 61.5% versus 87.2% and 91.5%, PPV of 31.8% versus 55.9% and 63.0%, NPV of 97.3% versus 96.2% and 94.7%, and accuracy of 66.4% versus 86.4% and 88.6% at antiheparin–PF4 ELISA thresholds ≥0.4, ≥0.8, and ≥1.0 OD units, respectively. Conclusion: Our study suggests an increased antiheparin–PF4 ELISA threshold of 0.8 or 1.0 OD units enhances specificity, PPV, and accuracy while maintaining NPV with decreased sensitivity.

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Highly Sensitive and Specific SARS-CoV-2 Serological Assay Using a Magnetic Modulation Biosensing System

Biosensors ◽

10.3390/bios12010007 ◽

2021 ◽

Vol 12 (1) ◽

pp. 7

Author(s):

Shira Avivi-Mintz ◽

Yaniv Lustig ◽

Victoria Indenbaum ◽

Eli Schwartz ◽

Amos Danielli

Keyword(s):

Viral Infections ◽

Limit Of Detection ◽

Turnaround Time ◽

Elisa Test ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Igg Antibodies ◽

Serological Assay ◽

Clinical Sensitivity ◽

Highly Sensitive

Sensitive serological assays are needed to provide valuable information about acute and past viral infections. For example, detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies could serve as the basis for an “immunity passport” that would enable individuals to travel internationally. Here, utilizing a novel Magnetic Modulation Biosensing (MMB) system and the receptor-binding domain of the SARS-CoV-2 spike protein, we demonstrate a highly sensitive and specific anti-SARS-CoV-2 IgG serological assay. Using anti-SARS-CoV-2 IgG antibodies, RT-qPCR SARS-CoV-2-positive and healthy patients’ samples, and vaccinees’ samples, we compare the MMB-based SARS-CoV-2 IgG assay’s analytical and clinical sensitivities to those of the enzyme-linked immunosorbent assay (ELISA). Compared with ELISA, the MMB-based assay has an ~6-fold lower limit of detection (129 ng/L vs. 817 ng/L), and it detects an increase in the IgG concentration much earlier after vaccination. Using 85 RT-qPCR SARS-CoV-2-positive samples and 79 -negative samples, the MMB-based assay demonstrated similar clinical specificity (98% vs. 99%) and sensitivity (93% vs. 92%) to the ELISA test, but with a much faster turnaround time (45 min vs. 245 min). The high analytical and clinical sensitivity, short turnaround time, and simplicity of the MMB-based assay makes it a preferred method for antibody detection.

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Complement Component C1q as an Emerging Biomarker for the Diagnosis of Tuberculous Pleural Effusion

Frontiers in Microbiology ◽

10.3389/fmicb.2021.765471 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xin Qiao ◽

Ming-Ming Shao ◽

Feng-Shuang Yi ◽

Huan-Zhong Shi

Keyword(s):

Pleural Effusion ◽

Confidence Interval ◽

Diagnostic Accuracy ◽

Predictive Value ◽

Complement Component ◽

Enzyme Linked Immunosorbent Assay ◽

Age And Gender ◽

Tuberculous Pleural Effusion ◽

And Gender ◽

Sensitivity Specificity

Background and Objective: The accurate differential diagnosis of tuberculous pleural effusion (TPE) from other exudative pleural effusions is often challenging. We aimed to validate the accuracy of complement component C1q in pleural fluid (PF) in diagnosing TPE.Methods: The level of C1q protein in the PF from 49 patients with TPE and 61 patients with non-tuberculous pleural effusion (non-TPE) was quantified by enzyme-linked immunosorbent assay, and the diagnostic performance was assessed by receiver operating characteristic (ROC) curves based on the age and gender of the patients.Results: The statistics showed that C1q could accurately diagnose TPE. Regardless of age and gender, with a cutoff of 6,883.9 ng/mL, the area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of C1q for discriminating TPE were 0.898 (95% confidence interval: 0.825–0.947), 91.8 (80.4–97.7), 80.3 (68.2–89.4), 78.9 (69.2–86.2), and 92.5 (82.6–96.9), respectively. In subgroup analysis, the greatest diagnostic accuracy was achieved in the younger group (≤ 50 years of age) with an AUC of 0.981 (95% confidence interval: 0.899–0.999) at the cutoff of 6,098.0 ng/mL. The sensitivity, specificity, PLR, NLR, PPV, and NPV of C1q were 95.0 (83.1–99.4), 92.3 (64.0–99.8), 97.4 (85.2–99.6), and 85.7 (60.6–95.9), respectively.Conclusion: Complement component C1q protein was validated by this study to be a promising biomarker for diagnosing TPE with high diagnostic accuracy, especially among younger patients.

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Agreement of Enzyme-Linked Immunosorbent Assay With Rapid Plasma Reagin and Treponema pallidum Hemagglutination Assay for Screening and Diagnosis of Syphilis at National Blood Bank Service in Addis Ababa, Ethiopia

American Journal of Clinical Pathology ◽

10.1093/ajcp/aqz131.007 ◽

2019 ◽

Vol 152 (Supplement_1) ◽

pp. S153-S154

Author(s):

Jemal Ibrahim ◽

Ejigayehu Afework ◽

Mintewab Hussein

Keyword(s):

Positive Predictive Value ◽

Predictive Value ◽

Addis Ababa ◽

Treponema Pallidum ◽

Blood Bank ◽

Enzyme Linked Immunosorbent Assay ◽

Rapid Plasma Reagin ◽

Hemagglutination Assay ◽

Kappa Value ◽

Sensitivity Specificity

Abstract Objectives To determine the agreement of enzyme-linked immunosorbent assay (ELISA) with rapid plasma reagin (RPR) and Treponema pallidum hemagglutination assay (TPHA) at the National Blood Bank Service in Addis Ababa, Ethiopia. Methods The study was conducted from January to June 2016 on 190 syphilis ELISA positive and 190 negative samples stored at the National Blood Bank Service (NBBS) laboratory, Addis Ababa, Ethiopia, from July 2015 to December 2015. A systematic random sampling method was used to select samples. The data were analyzed by SPSS version 20 software. The overall percent agreement, kappa value, sensitivity, specificity, positive predictive value, and negative predictive value of the tests were calculated. Results From 190 positive sera, 151 (80%) were confirmed as positive by TPHA, and 39 (20%) were found false positive; 59 (31.1%) of them were positive and 131 (68.9%) were false positive by RPR. From 190 negative sera, all were negative by RPR and TPHA. The sensitivity, specificity, positive predictive value, and negative predictive value of TPHA were 99.9%, 85%, 79%, and 100%, respectively, while RPR was 62%, 99%, 100%, and 63%, respectively. Overall percent agreement of ELISA with TPHA was 90% and corresponding kappa value was 0.795, and ELISA with RPR was 66% with a kappa value of 0.375. Conclusion TPHA was very sensitive; there was substantial agreement with ELISA. Whereas RPR was highly specific and less sensitive, there was fair agreement with ELISA. TPHA can be used interchangeably with ELISA to screen blood in blood bank laboratories.

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Sensitivity and Kinetics of an NS1-Based Zika Virus Enzyme-Linked Immunosorbent Assay in Zika Virus-Infected Travelers from Israel, the Czech Republic, Italy, Belgium, Germany, and Chile

Journal of Clinical Microbiology ◽

10.1128/jcm.00346-17 ◽

2017 ◽

Vol 55 (6) ◽

pp. 1894-1901 ◽

Cited By ~ 48

Author(s):

Yaniv Lustig ◽

Hana Zelena ◽

Giulietta Venturi ◽

Marjan Van Esbroeck ◽

Camilla Rothe ◽

...

Keyword(s):

Czech Republic ◽

Immunosorbent Assay ◽

Zika Virus ◽

False Negative ◽

Cross Reactivity ◽

Diagnostic Methods ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Igg Antibodies ◽

Kinetics Of

ABSTRACT Serological diagnosis of Zika virus is challenging due to high cross-reactivity of Zika virus with other flavivirus antibodies. Recently, a Zika NS1-based enzyme-linked immunosorbent assay (ELISA) was developed and shown to be highly specific for Zika antibody detection; however, sensitivity was evaluated for only a small number of confirmed Zika-infected patients. In this study, we measured the sensitivity and kinetics of Zika IgM and IgG antibodies using the Zika NS1-based ELISA in 105 samples from 63 returning travelers infected with Zika virus (proven by PCR or neutralization assay) from Israel, Czech Republic, Italy, Belgium, Germany, and Chile. Zika virus IgM was detected from 2 to 42 days post-symptom onset (PSO) with an overall sensitivity of 79% in the first month and 68% until 2 months PSO, while IgG antibodies were detected from 5 days to 3 years PSO with 79% sensitivity. Interestingly, significant differences in IgM sensitivity and IgM detection period were observed between Israeli and European/Chilean Zika-infected travelers, adding to the complexity of Zika infection diagnosis and suggesting that other diagnostic methods should be complemented to reduce false-negative results.

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Two Methods for Rapid Serological Diagnosis of Acute Leptospirosis

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.8.2.349-351.2001 ◽

2001 ◽

Vol 8 (2) ◽

pp. 349-351 ◽

Cited By ~ 42

Author(s):

Paul N. Levett ◽

Songee L. Branch ◽

Carol U. Whittington ◽

Charles N. Edwards ◽

Helene Paxton

Keyword(s):

Positive Predictive Value ◽

Negative Predictive Value ◽

Predictive Value ◽

Immunoglobulin M ◽

Serological Diagnosis ◽

Enzyme Linked Immunosorbent Assay ◽

Rapid Assays ◽

Igm Elisa ◽

Highly Sensitive ◽

Specialized Equipment

ABSTRACT Leptospirosis is a common and underdiagnosed zoonosis. Two rapid assays for serological diagnosis of acute leptospirosis in diagnostic laboratories, the immunoglobulin M (IgM)-dipstick assay and the indirect hemagglutination assay (IHA), were evaluated and compared with standard assays. Sera were examined from 104 patients admitted to a hospital for investigation in a leptospirosis diagnostic protocol. Specimens for serology were taken on days 1 and 4 of the patients' hospital stay. Antibodies were detected using an IgM-enzyme-linked immunosorbent assay (ELISA), microscopic agglutination test (MAT), an IgM-dipstick assay, and an IHA. Fifty-one patients were found to have leptospirosis. The sensitivity of the IgM-dipstick assay was 98%, its specificity was 90.6%, its positive predictive value was 90.9%, and its negative predictive value was 98%. The sensitivity of the IHA was 92.2%, its specificity was 94.4%, its positive predictive value was 95.9%, and its negative predictive value was 92.7%. The standard IgM-ELISA and MAT, were positive in the first samples tested from 67 and 55% of the cases, respectively, and the rapid IgM-dipstick assay and IHA were positive in 71 and 49%, respectively, in the first sample tested. Both rapid assays are highly sensitive and specific. Neither requires specialized equipment, and both are suitable for use in diagnostic laboratories.

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