The sensitivity and specificity of Lassa virus IgM by ELISA as screening tool at early phase of Lassa fever infection.

Autor: Ibekwe TS; The Research Unit, Lassa Fever Research and Diagnostic Centre, Irrua Specialist Teaching Hospital, Irrua, Nigeria ; Department of Ear, Nose, and Throat, College of Health Sciences, University of Abuja, Nigeria., Nwegbu MM, Asogun D, Adomeh DI, Okokhere PO
Jazyk: angličtina
Zdroj: Nigerian medical journal : journal of the Nigeria Medical Association [Niger Med J] 2012 Oct; Vol. 53 (4), pp. 196-9.
DOI: 10.4103/0300-1652.107552
Abstrakt: Background: Early diagnosis, prompt treatment, and disease containment are vital measures in the management of Lassa fever (LF), a lethal and contagious arenaviral hemorrhagic disease prevalent in West Africa. Lassa Virus (LAV)-specific Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) test, the gold standard for diagnosis, is unavailable in most centers. Serologic detection of LAV IgM is a more accessible tool and this work was to investigate its adequacy as an early marker for LF.
Patients and Methods: A prospective case-control study conducted July 2007-March 2011 in a tertiary referral health center in Nigeria. Blood samples for test and control were evaluated for Lassa specific antigens and IgM using RT-PCR (primers S36+ and LVS 339) and indirect ELISA (Lassa Nucleo-protein (NP)-Antigen) respectively. RT-PCR outcome was used as standard to test for the sensitivity and specificity of IgM.
Results: Of the 37 confirmed cases of LF infection by RT-PCR, 21 (57%) were IgM positive. Amongst the 35 confirmed negative cases (control group), eight were IgM positive. The diagnostic sensitivity and specificity of the IgM assay were 57% and 77% respectively. The negative and positive predictive values of the IgM serological assay were 63% and 72%, respectively, while the efficiency of the test was 67%.
Conclusion: The specificity and sensitivity of IgM as a screening tool for early detection of LF appear weak and, hence, the need for a reliable LF "rapid screening kit" since RT-PCR is unavailable in most centers. In the interim, "high clinical index of suspicion," irrespective of IgM status, requires urgent referral to confirmatory centers.
Databáze: MEDLINE
Externí odkaz: