Determine the percentage of fetal red blood cells from the total red cells counted using the Kleihauer-Betke Method in the determination of feto-maternal hemorrhage.
Formula:
Fetal Red Cells (%) = Number of Fetal Red Cells / Total Red Cells Counted x 100
Principle:
The Kleihauer-Betke test distinguishes between fetal and maternal blood cells based on the type of hemoglobin that is present. Red blood cells containing fetal hemoglobin are more resistant to acid than those containing adult hemoglobin. When a sample of maternal blood is exposed to an acid, the maternal hemoglobin washes away, while the fetal hemoglobin remains intact. After this acid elution, the slide is washed, stained, and examined under the microscope. The fetal cells will be red and easy to see, while the maternal cells will look pale because they have lost most of their hemoglobin. The number of fetal cells is then counted to estimate the total volume of fetal blood.
