Sign in →

Test Code BLOD0978 Fetal Screen

Useful For

The detection of Rh positive red blood cells in Rh negative mothers due to a feto-maternal hemorrhage.


At delivery, a variable volume of fetal blood enters the maternal circulation when the placenta separates from the uterine wall.  In susceptible patients, this event may give rise to the production of maternal alloantibodies (Rh immunization).  In most instances, Rh negative mothers delivering Rh positive infants can be protected from producing anti-D by the administration of Rhogam within 72 hours of delivery.  A 300 ug dose of Rhogam is sufficient to suppress Rh immunization for no more than 30 mL of fetal whole blood that has entered the maternal circulation.  The fetal screen test is used to detect a feto-maternal hemorrhage of an amount greater than that covered by the standard 300 ug dose of Rhogam. 


Erythrocyte Rosetting

Performing Laboratory

Bozeman Health Laboratory Services

Specimen Requirements

Specimen Type: EDTA whole blood

Container/Tube: Purple top or pink top (K2 EDTA)

Specimen Volume: 3 mL

Collection Instructions:  Collect blood from mother at least 1 hour after delivery of all products of conception and collect as soon as possible thereafter.  Do not centrifuge. Forward unprocessed whole blood promptly.  Rhogam must be given within 72 hours of delivery.

Specimen Rejection: Gel tube

Specimen Transport Temperature

Ambient <24 hours/Refrigerated >24 hours

Specimen Stability

Specimen Type Temperature Time
Whole Blood EDTA Ambient 24 hours
  Refrigerated 48 hours


Reference Values

Negative-One dose of Rhogam considered sufficient


If the fetal screen is positive, a Kleihauer-Betke test will be automatically reflexed to quantitate the volume of feto-maternal hemorrhage in post-partum D-negative women.

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding