Accuracy of capillary blood sampling for diagnosing syphilis infection

Capillary blood collection presents advantages such as reduced invasiveness over venous serum for syphilis diagnosing. This study aimed to compare diagnostic accuracy between capillary and venous blood samples for syphilis diagnosis. Individuals aged ≥ 18 years were included in a cross-sectional study. Syphilis screening was done using Rapid tests (RT) followed by collection of serum capillary and venous samples for VDRL and TPHA test. Sensitivity, specificity, and Kappa coefficient were calculated. Of 191 participants, 115 RT + and 76 RT-. Diagnostic properties did not significantly differ between capillary and venous samples. Capillary VDRL showed 99% sensitivity and 100% specificity, mirroring TPHA results. Furthermore, there was significant agreement between sample types for both serological tests (p < 0.001). Capillary sampling offers comparable diagnostic accuracy to venous collection, regardless of serum quality. Capillary sampling holds promise, particularly in developing countries and large-scale testing initiatives.