A Comparative Evaluation Of Sensitivity And Specificity Of Qualitative Urine Pregnancy Tests With Rapid hCG Immunoenzymatic Test

Early diagnosis of pregnancy is very important to prevent fetal damage due to specific drug consumption and high-risk behaviors. The objective of this study was to compare the sensitivity and specificity of quantitative agglutination pregnancy tests in urine and rapid β hCG immunoenzymatic assay test in serum as a gold standard. This cross-sectional study was performed among 390 women who referred to healthcare centers where their urine samples were tested with latex agglutination (direct agglutination and agglutination inhibition) and the results were compared with rapid β hCG immunoenzymatic assay test in serum as a gold standard. The sensitivity of direct agglutination (82. 05 %) was more than that of agglutination inhibition (81. 2 %)، but the specificity of the tests were equal (99. 27 %). The agreement coefficients between direct agglutination and agglutination inhibition on the one hand and rapid β HCG immunoenzymatic assay on the other were 0. 859 and 0. 853، respectively. The possibility of negative results in direct agglutination is more than that of agglutination inhibition، but the specificity of both qualitative tests is equal. Besides، both tests may have an equal possibility of false positive results. Since the occurrence of false negative results in qualitative tests is higher than that in serum gold standard، the negative results of such tests should be confirmed with more sensitive methods such as rapid β hCG immunoenzymatic assay.