Which test is the most sensitive for detecting congenital syphilis?

The polymerase chain reaction (PCR) test is the most sensitive method for detecting congenital syphilis. This technique amplifies specific DNA sequences from the Treponema pallidum bacteria, allowing for the detection of even very low levels of the pathogen in clinical specimens such as blood or tissues. PCR is particularly valuable in cases of congenital syphilis because it can provide definitive evidence of the presence of the bacteria, even when other serological tests might not detect the infection adequately.

Congenital syphilis often presents with subtle signs and can be challenging to diagnose based on clinical findings or serological tests alone. Traditional tests like VDRL and RPR are less specific and may give false negatives, especially in infants. The microhemagglutinin test for T. pallidum (MHA-TP) is also sensitive but generally not utilized as the primary detection method in clinical practice for congenital cases. Hence, the PCR method stands out for its high sensitivity and specificity in identifying Treponema pallidum in infants suspected of congenital syphilis.