Laboratory Test Directory

FETAL Maternal hemorrhage SCREEN (007-0155) 

Synonyms: Fetal Screen, FMH, Rosette Test

CPT 4 Code: 85461

Test Order Mnemonic: FMH

Test Includes: Rosette test is to be done on postpartum maternal blood  to estimate the volume of fetal-maternal hemorrhage and the number of vials of Rh Immune Globulin to administer. Rh positive cells in the circulation of Rh negative patients will form rosettes (clumps) and subsequently react with R2R2 cells. This test detects an excessive hemorrhage of Rh positive fetal cells in an Rh negative mother. Fetal Hemoglobin stain will be performed to confirm and quantify any positive rosette tests.

Applies to:  Rh negative mothers within 72 hours of giving birth to a Rh-positive infant;  this test is not suitable for other patients or blood types.

Lab: Blood Bank

Request Form: Blood Bank Division Primary Request Form

Causes for Rejection: Gross hemolysis, serum separator tube, old specimen

Availability: Samples are accepted 24 hours per day at the Blood Bank Lab, McCullough 5.102

Turnaround Time: 2 hours if negative;  all positive tests will require FHS testing and an additional 2-4 hours of testing time

Special Instructions: All requests must include requesting physician’s name and ID number, patient's name, UH #, patient location, clinical information/diagnosis, identity of phlebotomist and date and time collected.  Specimen must be labeled with patient's full name, UH # and Date of Collection. Specimen must be transported to the laboratory in a biohazard specimen bag with request form in the pocket of the bag.  Request form must be filled out completely and all information must be legible. 

Specimen: Blood

Volume: 5 mL blood

Minimum Volume: 3 mL blood

Container: Lavender-topped tube (EDTA)

Reference Ranges: Negative