Performance of an automated chemiluminescent assay for the detection of anti-hepatitis A virus IgM antibodies: Access® HAV IgM assay

Abstract number: 1733_673

Buisson Y., Masson C., Bouniort F.

Background: The diagnosis of acute hepatitis A is based on the detection of anti-HAV IgM antibodies. A fully automated assay for the qualitative detection of anti-HAV IgM in human serum and plasma developed on the family of Access immunoassay systems from Beckman Coulter was studied and included imprecision, clinical sensitivity and specificity, comparison with a reference method and negative samples distribution.

Methods: Intra-assay imprecision based on 30 replicates of 4 samples (1 negative and 3 positive). Inter-assay imprecision based on the same 4 samples tested in 5 replicates, twice a day, 5 different days. Sensitivity was studied with a population of 210 individual samples from patients with acute hepatitis A and with 157 samples from 26 cases of clinical follow-up or seroconversion. Results obtained with the Access HAV IgM assay were compared with a commercially available EIA technique; discrepant results were confirmed using a third EIA method. The specificity of the Access HAV IgM assay was evaluated on a normal population (n = 1,535) and a population with a potentially interfering pathologies (HBV Ab, HIV Ab, HCV Ab, CMV, EBV, HSV, VZV, Yellow fever, Mumps, Measles, Polio, Rubella, Toxoplasmosis or auto-immune disorders (n = 429). A comparison study with a commercialised automated HAV IgM assay was performed with 620 samples. Discrepant results were confirmed using a third EIA method. The negative samples repartition was studied with 706 blood donor samples.

Results: Imprecision was less than 10% CV for the positive samples. Sensitivity was 99.04% with individual samples and 100% with seroconversion or clinical follow-up cases. The Access HAV IgM assay demonstrated a specificity of 99.93% with a normal population and 99.53% with the population of potentially interfering pathologies. The comparison study exhibited an overall agreement of 98.40%, a relative specificity of 99.35% and a relative sensitivity of 97.40%. After further analysis with a third EIA method, 7 from the 10 discrepant results were correctly tested with the Access HAV IgM assay. The negative sample distribution showed that 93.90% of the results are lower than 0.3 S/CO.

Conclusion: The Access HAV IgM assay combines robust analytical and clinical performance with good precision, sensitivity, specificity and a good distribution of the negative samples far away from the cut-off value: with the advantage of a rapid, automated, random access immunoassay system.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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