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Test Name:
Fetal-Maternal Bleed, Quantitation, by Flow Cytometry
- SBMF No:
36040 - Performance Lab Name:
Flow Cytometry/Molecular Pathology - Test Mnemonic:
FMH QUAN - ABN:
Not required - CPT Code:
88184 - LOINC Code:
18291-5; 55730-6; 10331-7; 1313-6 - Also Known As:
Fetal Quant by Flow
Kleihauer-Betke alternate - Also See:
22041 Fetal-Maternal Bleed, Qualitative - Spec Type:
Whole blood - Spec Container:
Lavender top (EDTA) tube - Pref Vol:
5.0-7.0 mL - Min Vol:
3.0 mL - Fasting:
No - Spec Collect:
Routine venipuncture
Tube must fill to one-half, or greater, of vacuum capacity
Immediately after collection, gently invert tube to mix
Collect antepartum specimen after fetal-maternal bleed
Collect postpartum specimen at least 1 hour after delivery or abortion, but within 72 hours of procedure - Spec Process:
Do not centrifuge
Do not remove plasma from cells - Spec Store Transport:
Refrigerated - Spec Stability:
6 hours room temperature (20-30°C)
5 days refrigerated (2-8°C)
Frozen (-20°C): Unacceptable - Spec Reject:
Hemolyzed, lipemic, or clotted sample - Methodology:
Flow Cytometry - Use:
This quantitative test should be ordered when it is necessary to measure antepartum fetal-maternal hemorrhage.
If the mother has had a positive result for the qualitative Fetal-Maternal Bleed Screen, this test is automatically performed to calculate the Rh immune globulin (RhoGAM) dosage to be administered. - Clinical Significance:
The test for fetal hemoglobin (HbF) determination can be used in the workup of possible cases of fetal-maternal hemorrhage. Examples of this condition include cases of trauma with suspected placental injury, after amniocentesis, or postpartum in situations of Rh incompatibility between mother and fetus. Rh (D) incompatibility exists when a D-negative mother is pregnant with a D-positive fetus. This occurs in 9–10% of pregnancies. Transplacental hemorrhage can lead to isoimmunization and possible hemolytic disease of subsequent D-positive pregnancies. The ability to quantify fetal-maternal hemorrhage is of clinical significance in the prophylactic treatment of D-negative mothers. Combined antenatal and postnatal therapy of Rh immune globulin (RhIg) can prevent isoimmunization of most women at risk. The amount of RhIg to be given is dependent upon the extent of fetal-maternal hemorrhage.
Compared to other methods for HbF determination, including the traditional Kleihauer-Betke (KB) acid elution technique, flow cytometry using monoclonal antibody directed against HbF has been shown to be far more sensitive in detecting small amounts of fetal blood (as much as 500 times more sensitive). It eliminates the subjectivity of the KB procedure and has been shown to reduce the number of false positives. Linearity (relationship of flow cytometry result to amount of fetal Hg) is also superior to that of the KB method. - Reference Range:
Equal to or less than 0.1% - Day Run:
Sat-Sun (daily) - Time Reported:
If ordered stat, within 4 hours of receipt in lab - Test Type:
OBSTETRIC-NEONATAL
