Abstract:

Objective To study the clinical value of Mycobacterium tuberculosis IgG and IgM antibody detection reagents.Methods The clinical value was detected in two study periods. In the first study period, the patients who visited the 309th Hospital of Chinese PLA in May 2014 were included. By retrospectively analyzing the medical records, there were 92 patients with pulmonary tuberculosis (TB) and 99 patients without TB. Ninety-four healthy volunteers in the same period were selected as controls. In the second study period, 118 patients who visited the 309th Hospital of Chinese PLA between December 2016 and March 2017 were collected, including 62 cases with pulmonary TB and 56 patients without TB. The samples of all subjects were collected for smear detection and evaluation using Mycobacterium tuberculosis IgG and IgM antibody detection kit (i.e. Immune colloidal gold technique).Results In the first study, the sensitivity, specificity, positive predictive value, negative predictive value and consistency rate of IgG and IgM antibody detection were 64.1% (59/92), 89.1% (172/193), 73.8% (59/80), 83.9% (172/205) and 81.1% (231/285), respectively. Of the 92 pulmonary TB cases, the positive rate of IgG antibody detection was 64.1%. The positive rate was 73.8% (31/42) in the smear-positive pulmonary TB cases and 56.0% (28/50) in the smear-negative pulmonary TB cases; the difference was not statistical significant (χ ²=3.15, P=0.076). All pulmonary TB cases were detected as negative by IgM antibody detection. In the second study, the sensitivity, specificity, positive predictive value, negative predictive value and consistency rate of IgG and IgM antibody detection for the TB diagnosis were 45.2% (28/62), 78.6% (44/56), 70.7% (29/41), 57.1% (44/77) and 61.9% (73/118), respectively. Among the 62 pulmonary TB cases, the positive rate of IgG antibody detection was 45.2% (28/62). The positive rate was 56.3% (18/32) in the smear-positive pulmonary TB cases, which was significantly higher than that of 29.2% (7/24) in the smear-negative pulmonary TB cases (χ ²=4.07, P=0.044). Whereas there was only one case detected as positive by IgM antibody detection, yielding a positive rate of 1.6% (1/62). Conclusion The IgG in Mycobacterium tuberculosis IgG and IgM antibody tests had a better auxiliary diagnostic value for active TB, while the clinical value of IgM test requires to be further evaluated.

Key words: Mycobacterium tuberculosis, Antibodies, Immunoglobulin G, Immunoglobulin M, Reagent kits, diagnostic, Evaluation studies