Evaluation of the Analytical Performance of a Rapid hCG Pregnancy Test Applied to Blood Specimens
Keywords:
hCG, Pregnancy testing, Rapid test kitAbstract
Rapid urine-based pregnancy tests may yield false- negative results in very early pregnancy due to insufficient levels of human chorionic gonadotropin (hCG). This experimental study aimed to evaluate the diagnostic performance and determine the limit of detection (LOD) of a urine hCG pregnancy test when applied to blood specimens. A total of 155 participants were enrolled at Wachirabarami Hospital, including pregnant women (positive group) and male participants (negative group). The RightSign® hCG Pregnancy (urine) test was used to analyze blood samples (whole blood, serum, and plasma), and the results were compared with urine test outcomes. Serial dilution of serum samples was performed to identify the lowest detectable hCG concentration. The results demonstrated excellent diagnostic performance when the urine pregnancy test was applied to blood samples, with a sensitivity of 100% (95% CI: 94.0–100%), specificity of 100% (95% CI: 96.2–100%), and overall accuracy of 100% (95% CI: 97.6–100%). Notably, the test was able to detect hCG levels in blood as low as 10.9 mIU/mL, which is lower than the standard detection threshold of urine-based pregnancy tests (25 mIU/mL). In conclusion, applying urine pregnancy test kits to blood samples is a reliable and highly sensitive approach that allows earlier detection of pregnancy than urine testing and provides novel evidence supporting a cost-effective and efficient alternative for rapid pregnancy screening in clinical settings.
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