Which test differentiate maternal and fetal blood cell (AIIMS May 2012)
|B||Osmotic fragility test|
|C||Betke ("KB") test|
a. The Apt test is most commonly used in cases of vaginal bleeding late during to determine if the bleeding is from the mother or the fetus.
i. A positive test would indicate that blood is of fetal origin, and
ii. A negative test indicates that the blood is of maternal origin.
b. Fetal hemoglobin is resistant to alkali (basic) denaturation, whereas adult hemoglobin is susceptible to such denaturation.
c. Therefore, exposing the blood specimen to sodium hydroxide (NaOH) or KOH will denature the adult but not the fetal hemoglobin.
d. The fetal hemoglobin will appear as a pinkish color under the microscope while the adult hemoglobin will appear as a yellow-brownish color
e. The Kleihauer–Betke ("KB") test, is a blood test used to measure the amount of fetal hemoglobin transferred from a fetus to a mother's bloodstream. It is usually performed on Rhesus-negative mothers.