Detect and quantify the extent of fetomaternal hemorrhage in pregnant or postpartum women. Assess the need for Rh immunoglobulin (eg, RhoGAM) for fetomaternal hemorrhage.
- Patient Preparation
- Maternal, pregnant or post-partum whole blood.
- Lavender (EDTA) or pink (K2EDTA).
- Specimen Preparation
- Transport 5 mL whole blood. (Min: 0.5 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Frozen specimens. Clotted or hemolyzed specimens. Specimens older than 72 hours. Specimens from males or non-pregnant females.
- Ambient: 12 hours; Refrigerated: 72 hours; Frozen: Unacceptable
|% Fetal RBCs||The fetal RBC percentage is directly measured by flow cytometry and gives the percentage of fetal RBCs in maternal circulation resulting from recent fetal-maternal hemorrhage. Post-partum, some fetal cells are expected (0.04% plus or minus 0.024%, mean plus or minus SD).|
|Fetal Blood Volume||Fetal blood volume is the volume of feto-maternal hemorrhage and is calculated from the % Fetal RBCs by multiplying by 50, assuming a maternal blood volume of 5000 mL and a hematocrit of 50%. Post-partum, some feto-maternal hemorrhage is expected (2.0 mL plus or minus 1.2 mL, mean plus or minus SD).|
|RhIg Required||Given the delivery of an RhD+ fetus from an RhD- mother, the amount of IM RhIg (anti-RhD immunoglobulin) required to avoid sensitization is 10 µg for each mL of feto-maternal hemorrhage.|
|RhIg Vials Required||Given the delivery of an RhD+ fetus from an RhD- mother, one (1) vial of RhD (300 µg vial administered IM) is recommended when the amount of RhD required is <300 µg. From 300-600 µg, 2 vials are recommended; from 600-900 µg, 3 vials are recommended; from 900-1200 µg, 4 vials are recommended; from 1200-1500 µg, 5 vials are recommended and so forth.|
For routine fetal hemoglobin (Hb F) testing, please order Hemoglobin Evaluation with Reflex to Electrophoresis and/or RBC Solubility (0050610).
|Component Test Code*||Component Chart Name||LOINC|
|2001744||Fetal Hgb - Fetal Blood Volume||55730-6|
|2001745||Fetal Hgb - RhIg Vials Required||1313-6|
|2001746||Fetal Hgb - RhIg Required||55731-4|
|2001788||Fetal Hgb - Percent Fetal RBCs||55729-8|
- Fetal Hemoglobin
- Fetal Maternal Bleed
- Fetal Maternal Erythrocyte Distribution, Blood
- Fetal-Maternal Erythrocyte Differentiation
- Fetomaternal Bleed by Flow Cytometry (Blood)
- Kleihauer Acid Elution (Fetal RBCs)
- Kleihauer-Betke Acid Elution for Fetal RBC Detection
- Maternal Erythrocyte Diff
- RhoGAM determination