Diagnosis of toxoplasmosis in newborn is done by?
**Core Concept**
Toxoplasmosis is a parasitic infection caused by Toxoplasma gondii, which can be transmitted to the fetus during pregnancy, leading to congenital toxoplasmosis. Diagnosis in newborns is crucial to prevent complications.
**Why the Correct Answer is Right**
The diagnosis of toxoplasmosis in newborns is typically done by detecting the presence of Toxoplasma gondii antibodies in the infant's blood. This is usually done through a test called the immunoglobulin M (IgM) antibody test, which detects the presence of IgM antibodies against Toxoplasma gondii. IgM antibodies are typically produced in response to a recent infection, making this test a reliable indicator of congenital toxoplasmosis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because PCR (Polymerase Chain Reaction) is a molecular test used to detect the presence of Toxoplasma gondii DNA, but it is not the primary method used for diagnosis in newborns.
**Option B:** This option is incorrect because serology tests, such as the Sabin-Feldman dye test, are used to detect antibodies against Toxoplasma gondii, but they are not specific to detecting congenital toxoplasmosis in newborns.
**Option C:** This option is incorrect because ultrasound and other imaging studies may show signs of congenital toxoplasmosis, but they are not definitive diagnostic tests.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the presence of IgM antibodies against Toxoplasma gondii in a newborn is a strong indicator of congenital toxoplasmosis, but it does not necessarily confirm the diagnosis. A thorough clinical evaluation and additional diagnostic tests, such as PCR and serology, should be performed to confirm the diagnosis.
**Correct Answer:** B. Serology tests, including the IgM antibody test, are used to diagnose toxoplasmosis in newborns.