Fetal Hemoglobin Determination for Fetomaternal Hemorrhage
Also known as: FHGB
Use
The Fetal Hemoglobin Determination test is designed to detect and quantify the extent of fetomaternal hemorrhage in pregnant or postpartum women. This is critical for assessing the need for Rh immunoglobulin (e.g., RhoGAM) in cases of suspected fetomaternal hemorrhage, which can occur during pregnancy or after childbirth. By determining the percentage of fetal red blood cells (RBCs) in the maternal circulation using flow cytometry, healthcare providers can accurately calculate the necessary dosage of RhIG and intervene appropriately to prevent hemolytic disease and other complications that may arise from fetal-maternal blood mixing.
Special Instructions
This test is specifically for use in pregnant or postpartum women who need assessment for Rh immune globulin or fetal-maternal bleeds. For routine fetal hemoglobin testing, consider ordering the Hemoglobin Evaluation with Reflex to Electrophoresis and/or RBC Solubility test (ARUP test code 0050610). Specimens from New York clients will be sent to a New York state-approved laboratory.
Limitations
The test is not suitable for males or nonpregnant females. Accurate calculation of RhIG dosage requires consideration of maternal height and weight, and users are advised to refer to the most recent AABB Technical Manual for guidance. Clotted or hemolyzed specimens are unacceptable, as are refrigerated specimens older than 120 hours (5 days) or ambient specimens older than 12 hours. Frozen specimens are also unacceptable, necessitating careful handling and timing of specimen transport and analysis.
Methodology
Cell-based / Cytometry (Flow Cytometry)
Biomarkers
LOINC Codes
- 55729-8
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
5 mL
Minimum Volume
0.5 mL
Container
Lavender (EDTA) or pink (K2EDTA)
Collection Instructions
Collect lavender (EDTA) or pink (K2EDTA). New York State Clients: Collect and ship Monday-Thursday only. Ship same day as collection.
Patient Preparation
Maternal, pregnant or postpartum whole blood.
Storage Instructions
Refrigerated.
Causes for Rejection
Clotted or hemolyzed specimens; refrigerated specimens greater than 120 hours old; ambient specimens greater than 12 hours old; specimens from males or nonpregnant females.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 12 hours |
| Refrigerated | 120 hours (5 days) |
| Frozen | Unacceptable |