Test ID: FMBNY
Fetomaternal Bleed, New York
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Determining the volume of fetal-to-maternal hemorrhage for the purposes of recommending an increased dose of the Rh immune globulin
Method Name A short description of the method used to perform the test
Hemoglobin F: Fetal Cell Detection by Flow Cytometry
RhD: Standard AABB
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Fetal Maternal Bleed
Fetal Maternal Erythrocyte Distribution, Blood
Fetal Red Cells for Fetal Maternal Erythrocyte Distribution
Fetal-Maternal Erythrocyte Differentiation
Kleihauer Acid Elution (Fetal RBC's)
Kleihauer-Betke
Maternal Erythrocyte Diff
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen must arrive within 72 hours (preferably 24 hours) of draw.
The New York State Department of Health recommends samples be tested within 30 hours of draw.
Container/Tube: Lavender top (EDTA)
Specimen Volume: Full tube
Collection Instructions:
1. Do not centrifuge or aliquot.
2. Invert several times to mix blood.
3. Send specimen in original tube.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild reject; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross reject |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood EDTA | Refrigerated (preferred) | 72 hours |
| Ambient | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
In hemolytic disease of the newborn, fetal red cells become coated with IgG alloantibody of maternal origin, directed against an antigen on the fetal cells that is of paternal origin and absent on maternal cells. The IgG-coated cells undergo accelerated destruction, both before and after birth. The clinical severity of the disease can vary from intrauterine death to hematological abnormalities detected only if blood from an apparently healthy infant is subject to serologic testing.
Pregnancy causes immunization when fetal red cells possessing a paternal antigen foreign to the mother enter the maternal circulation, an event described as fetomaternal hemorrhage (FMH). FMH occurs in up to 75% of pregnancies, usually during the third trimester and immediately after delivery. Delivery is the most common immunizing event, but fetal red cells can also enter the mother's circulation after amniocentesis, spontaneous or induced abortion, chorionic villus sampling, cordocentesis, or rupture of an ectopic pregnancy, as well as blunt trauma to the abdomen.(2)
Rh immune globulin (RhIG, anti-D antibody) is given to Rh-negative mothers who are pregnant with an Rh-positive fetus. Anti-D antibody binds to fetal D-positive red cells, preventing development of the maternal immune response. RhIG can be given either before or after delivery. The volume of FMH determines the dose of RhIG to be administered.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
< or =0.75 mL of fetal RBCs in normal adults
Interpretation Provides information to assist in interpretation of the test results
Greater than 15 mL of fetal RBCs (30 mL of fetal whole blood) is consistent with significant fetomaternal hemorrhage (FMH).
A recommended dose of Rh immune globulin (RhIG) will be reported for all Rh-negative maternal specimens. No dose recommendations will be made for Rh-positive maternal specimens. One 300 mcg dose of RhIG protects against a FMH of 30 mL of D-positive fetal whole blood or 15 mL of D-positive fetal red blood cells. Recommended standard of practice is to administer RhIG within 72 hours of the fetomaternal bleed for optimal protective effects. The effectiveness of RhIG decreases beyond 72 hours post-exposure but may still be clinically warranted. This assay has been validated out to 5 days post collection.
Mothers who are weak D express decreased amounts or only a portion of the D antigen that constitutes the Rh status of red blood cells. Local standards of care vary as to whether these mothers should receive a dose of RhIG. If the mother is determined to be weak D, a RhIG dose will be reported but the ordering physician should consult local experts to determine if RhIG is given as the local standard of care.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Clinical conditions exist that may result in an increased level of fetal hemoglobin-containing red cells, including hereditary persistence of fetal hemoglobin (HPFH) and thalassemia. Such red cells (also referred to as F cells) are detected by this assay. Results must be interpreted with caution in these situations.
This assay does not sensitively test for weak D and should not be used to make this determination for purposes other than Rh immune globulin.
This test is not used to detect the hereditary persistence of fetal hemoglobin (see HPFH/8270 Hemoglobin F, Red Cell Distribution, Blood).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Iyer R, Mcelhinney B, Heasley N, et al: False positive Kleihauer tests and unnecessary administration of anti-D immunoglobulin. Clin Lab Haematol 2003;25:405-408
2. Technical Manual. Sixteenth edition. Edited by J Roback, MR Combs, B Grossman, C Hillyer. Bethesda, MD, AABB Press, 2008, pp 625-637, pp 888
Method Description Describes how the test is performed and provides a method-specific reference
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. The flow cytometry method is adapted from the Caltag package insert.(Caltag Laboratories, Monoclonal Antibodies directed to human fetal hemoglobin (HbF), P/N L13011, Rev. 01-03. Davis BH, Olsen S, Biglelow NC, et al: Detection of fetal red cells in fetomaternal hemorrhage using a fatal hemoglobin monoclonal antibody by flow cytometry. Transfusion 1998;38:749-756)
RhD-Agglutination of red cells with an antiserum represents the presence of the corresponding antigen in the red cells.(Technical Manual. Sixteenth edition. Edited by J Roback, MR Combs, B Grossman, C Hillyer. Bethesda, MD, AABB Press, 2008)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Varies
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
86901-Rh
88184-Flow cytometry; cell surface cytoplasmic
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 28204 | Mother's Rh | 10331-7 |
| 28202 | Fetal-Maternal Bleed | 55730-6 |
| 28203 | Rh Immune Globulin | 55731-4 |
| 28246 | Remarks | In Process |
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