Time Sensitive

Ordering Recommendation

Detect and quantify the extent of fetomaternal hemorrhage in pregnant or postpartum women. Assess the need for Rh immunoglobulin (eg, RhoGAM) for fetomaternal hemorrhage.

New York DOH Approval Status

Testing is not New York state approved. Specimens from New York clients will be sent out to a New York state-approved laboratory.

Specimen Required

Patient Preparation

Maternal, pregnant or postpartum whole blood.


Lavender (EDTA) or pink (K2EDTA).
New York State Clients: Lavender (EDTA). Collect and ship Monday-Thursday only. Ship same day as collection.

Specimen Preparation

Transport 5 mL whole blood. (Min: 0.5 mL)
New York State Clients: Transport 5 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Clotted or hemolyzed specimens. Refrigerated specimens greater than 120 hours (5 days) old; Ambient specimens greater than 12 hours old. Specimens from males or nonpregnant females.


Ambient: 12 hours; Refrigerated: 120 (5 days) hours; Frozen: Unacceptable


Quantitative Flow Cytometry




1-2 days

Reference Interval


Interpretive Data

% Fetal RBCs The fetal RBC percentage is directly measured by flow cytometry and gives the percentage of fetal RBCs in the maternal circulation resulting from recent fetal-maternal hemorrhage. For accurate calculation of RhIG dosage that includes maternal height and weight, please refer to the most recent AABB Technical Manual.

Compliance Category

Laboratory Developed Test (LDT)


This test should only be used to detect and quantify the extent of fetomaternal hemorrhage, in pregnant or postpartum women who need to be assessed for Rh immune globulin (e.g. RhoGAM®) or fetal-maternal bleeds. 

For routine fetal hemoglobin (Hb F) testing, please order Hemoglobin Evaluation with Reflex to Electrophoresis and/or RBC Solubility (ARUP test code 0050610).

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
2001788 Fetal Hgb - Percent Fetal RBCs 55729-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • 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
  • Kleihauer-Betke Acid Elution for Fetal RBC Detection
  • Maternal Erythrocyte Diff
  • RhoGAM determination
Fetal Hemoglobin Determination for Fetomaternal Hemorrhage