The test is done to diagnose syphilis in a newborn if the mother is syphilitic is
**Core Concept**
The question is testing the knowledge of a diagnostic test used to detect congenital syphilis in newborns, which is a serious condition caused by the transmission of syphilis from an infected mother to her child during pregnancy.
**Why the Correct Answer is Right**
The Venereal Disease Research Laboratory (VDRL) test is a non-treponemal test used to diagnose syphilis, including congenital syphilis. It detects antibodies against the lipoidal material released from damaged host cells and the lipids from the treponeme (the causative agent of syphilis). This test is commonly used in newborns whose mothers have syphilis, as it can confirm the presence of syphilis infection in the infant. The VDRL test is often used in combination with the Treponema pallidum hemagglutination assay (TPHA) to confirm the diagnosis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a diagnostic test for syphilis in newborns.
* **Option B:** While the VDRL test is used to diagnose syphilis, it is not the only test used, and this option is incomplete.
* **Option D:** This option is not a diagnostic test for syphilis in newborns.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the VDRL test can produce false-positive results in newborns due to the presence of maternal antibodies. Therefore, confirmatory tests like the TPHA are often used to confirm the diagnosis of congenital syphilis.
**Correct Answer: C. VDRL test.**