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Test Code Billings Clinic: 5184 Fetal Blood Screen, Blood

Performing Laboratory

Billings Clinic Laboratory:  Blood Bank

Useful For

  • Screens for the presence of D(Rho) positive fetal cells in a sample of maternal whole blood following delivery.
  • Rh-negative maternal sensitization to positive fetal cells can be prevented by the injection of Rh immune globulin prior to and/or immediately following 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 Rh immune globulin to prevent maternal sensitization.

Methodology

Rosette

Specimen Requirements

  • Ideally, the maternal blood specimen should be drawn within 1 hour after delivery.
  • Specimen must arrive within 24 hours of draw.
  • Draw blood in a lavender-top (EDTA) tube(s), and send 4 mL of unprocessed EDTA whole blood.
  • Do not centrifuge.
  • Clotted blood may be used but not preferred.
  • Forward unprocessed whole blood promptly.
  • Note:  Date of delivery or abortion and date and time of draw are required on request form for processing.

Reference Values

Negative (must not be interpreted as indicating that Rh-immune globulin is not required)

 

False-negative results may be obtained if maternal antibody sensitizes and removes the fetal red blood cells from the circulation before the specimen is drawn.

Day(s) Test Set Up

Daily

Test Classification and CPT Coding

85461 - rosette

85460 - Kleihauer-Betke (if appropriate)

Profile/Testing Information

Reflex Information:

  • If positive, this test will reflex to Billings Clinic: #8585 “Kleihauer-Betke Stain, Blood", to be performed at St. Vincent's Hospital Laboratory.
  • This test may automatically reflex to other tests. An additional fee may be added.
  • The ordering physician/provider must indicate if the reflex test is NOT DESIRED. Indicate on order if no reflex test is desired.
  • To detect fetal-maternal bleeds in prenatal specimens and specimens from Rh-positive patients; order Billings Clinic: #8585 “Kleihauer-Betke Stain, Blood.”