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Fetal Screen
Test CodeFMS
Alias/See Also
Fetal Maternal Screen,
CPT Codes
86850
Preferred Specimen
BB PINK (PBB)
The blood specimen must be collected from the MOTHER after delivery of all products of conception. It is best to wait about an hour after delivery to allow any fetal blood to mix thoroughly in the maternal circulation.
The blood specimen must be collected from the MOTHER after delivery of all products of conception. It is best to wait about an hour after delivery to allow any fetal blood to mix thoroughly in the maternal circulation.
Specimen Stability
If there is a delay in testing, store the specimen at 2-6ºC.
Reference Range
Negative
Note: A positive test merely provides evidence of a potentially large feto-maternal bleed and a quantitative test will be required to determine the volume of the feto-maternal hemorrhage. Reflex to Kleihauer-Betke Test to determine the RHIG amount.
Clinical Significance
Hemolytic disease of the newborn as a result of maternal sensitization to the D (Rho) antigen on fetal red cells can be prevented by the injection of Rh immune globulin (RhIg) prior to and/or within 72 hours of delivery of an Rh-positive infant.
In certain instances a larger than usual volume of fetal blood may enter the maternal circulation, compromising the ability of the antibody present in a single dose of RhIg to prevent immunization. One dose of RhIg can protect against Rh immunization when the challenge consists of 15mL of fetal red blood cells (equivalent to 30 mL whole blood).
The FMH Rapid Screen test is a qualitative procedure by which massive fetal-maternal hemorrhages may be identified and which may require additional doses of RhIg. A quantitative procedure, such as the Kleihauer-Betke (KB) stain, must then be performed to determine the extent of the fetal-maternal hemorrhage and a dosage of RhIg calculated from the test results for this procedure.
In certain instances a larger than usual volume of fetal blood may enter the maternal circulation, compromising the ability of the antibody present in a single dose of RhIg to prevent immunization. One dose of RhIg can protect against Rh immunization when the challenge consists of 15mL of fetal red blood cells (equivalent to 30 mL whole blood).
The FMH Rapid Screen test is a qualitative procedure by which massive fetal-maternal hemorrhages may be identified and which may require additional doses of RhIg. A quantitative procedure, such as the Kleihauer-Betke (KB) stain, must then be performed to determine the extent of the fetal-maternal hemorrhage and a dosage of RhIg calculated from the test results for this procedure.
Performing Laboratory
CRMC Laboratory
CCMC Laboratory
FHSH Laboratory
