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HelpOrder Code LABFMB Fetomaternal Bleed, Flow Cytometry, Blood
Additional Codes
Mayo Test ID: FMB
EPIC Order Code: LABFMB
Reporting Name
Fetomaternal Bleed,Flow Cytometry,BUseful For
Determining the volume of fetal-to-maternal hemorrhage for the purposes of recommending an increased dose of the Rh immune globulin
Specimen Type
Whole Blood EDTAOrdering Guidance
This test is for the detection of fetal bleed, it should not be used to detect the hereditary persistence of fetal hemoglobin (HPFH) or to detect fetal maternal hemorrhage in a mother with HPFH. For HPFH diagnosis, order HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood.
NY State Clients: Testing is available; order FMBNY / Fetomaternal Bleed, New York, Blood.
Shipping Instructions
Specimen must arrive within 5 days (preferably 24-72 hours) of collection.
Specimen Required
Container/Tube: Lavender top (EDTA)
Specimen Volume: 6 mL
Collection Instructions:
1. Fill evacuated tube as completely as possible.
2. Do not centrifuge.
3. Invert several times to mix blood.
4. Send whole blood specimen in original tube. Do not aliquot as aliquoting into or out of a sample tube can adversely affect test results.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Refrigerated (preferred) | 5 days | |
| Ambient | 5 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
| Clotted blood | Reject |
Reference Values
≤3.75 mL of fetal red blood cells in normal adults
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Day(s) Performed
Monday through Sunday
Method Name
Flow Cytometry
CPT Code Information
88184-Flow cytometry, cell surface, cytoplasmic
Method Description
The fetomaternal bleed test identifies cells containing fetal hemoglobin. The cells are fixed and permeabilized and then incubated with monoclonal antibodies directed against fetal hemoglobin (HbF) and subsequently analyzed by flow cytometric methods. This test uses the US Food and Drug Administration-approved Invitrogen Fetal Hemoglobin kit with fluorescein isothiocyanate-conjugated monoclonal antibody directed to HbF (HFH-01).(Package insert: Invitrogen Fetal Hemoglobin Test Kit with FITC-conjugated Monoclonal Antibody Directed to HbF. Life Technologies Corporation; MAN 0003641, Rev 3.02 03/06/2013)
Rh immune globulin (RhIG) dose calculation: mL of fetal bleed/15 equals the calculated doses of RhIG, then add a safety margin, ie, when the number to the right of the decimal point is less than 5, round down and add 1 dose (example: 2.2 = 2.0 + 1 = 3); when the number to the right of the decimal point is 5 or greater, round up to the next number and add 1 dose (example: 2.8 = 3.0 + 1 = 4). If fetal bleed is 1.5 mL or less, it will be reported as negative bleed and the RhIG dose will be 1.
RhD-Agglutination of red blood cells with an antiserum represents the presence of the corresponding antigen in the red blood cells.(Cohn CS, Delaney M, Johnson ST, Katz LM, eds. Technical Manual. 20th ed. AABB Press; 2020)