Test used to differentiate between maternal and fetal blood in a given sample:(AIIMS May 2013, May 2012)
**Core Concept**
The question requires identification of a laboratory test used to distinguish between maternal and fetal blood, which is crucial in obstetrics and gynecology for diagnosing and managing various conditions, including fetal-maternal hemorrhage and preeclampsia.
**Why the Correct Answer is Right**
The correct answer is the Kleihauer-Betke test, which is a sensitive and specific method used to detect fetal hemoglobin in maternal blood. This test exploits the fact that fetal hemoglobin is more resistant to acid elution than adult hemoglobin. When the blood sample is treated with acid, adult hemoglobin is eluted, leaving behind fetal hemoglobin, which can be visualized using a special stain. This allows for the detection and quantification of fetal-maternal hemorrhage.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the differentiation between maternal and fetal blood.
* **Option B:** This option is not a valid test for distinguishing between maternal and fetal blood.
* **Option C:** This option is incorrect because it is not the primary test used for this purpose.
**Clinical Pearl / High-Yield Fact**
The Kleihauer-Betke test is also used to estimate the volume of fetal-maternal hemorrhage, which is essential for managing at-risk pregnancies.
**Correct Answer:** C. Kleihauer-Betke test.