Comparison of the diagnostic value of local Widal slide test with imported Widal slide test.

ABSTRACT

A laboratory study comparing the Widal slide agglutination test using local antigens produced by Mekar Jaya Diagnostica (SAT-MJD) with imported antigens (Murex, Abbott) was carried out on 55 sera of typhoid fever patients with positive blood culture and 56 sera of non-typhoid febrile patients. The SAT-MJD antigens consisted of a mixture of 5 different phage-types of S. typhi dominantly found in Indonesia. This study revealed the following results: the diagnostic sensitivity of local and imported antigens was 83.93%, the diagnostic specificity of local antigens was higher than the imported antigens ie 82.14% compared with 64.28%, the diagnostic efficiency of local antigens was 82.88% compared with 73.87% of the imported antigens. The diagnostic positive and negative predictive values of the local antigens were 80.70% and 83.63%, respectively. The imported antigen revealed diagnostic positive and negative predictive values of 69.69% and 80%, respectively. The diagnostic specificity and efficiency of local antigens were significantly different (p < 0.02 and p < 0.05) from the imported antigens. The local antigens have some advantages. There was no variation in within-run and between-day test, compared with a 6.6% variation shown by the imported antigen. The test results obtained 5 minutes after mixing the serum with antigens reduced the possibility of false-positive and false-negative results. The cost of local antigens is lower than the imported antigens. Based on these data, the Widal SAT-MJD has a reliable diagnostic value and can be used in small laboratories, such as primary health centers (Puskesmas).