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.


Quantitative Flow Cytometry




1-2 days

New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
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

Reference Interval

By report

Interpretive Data

The performance characteristics of this test were determined by ARUP Laboratories, Inc. 

% 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. Post-partum, some fetal cells are expected (0.04% plus or minus 0.024%, mean plus or minus SD). For accurate calculation of RhIG dosage that includes maternal height and weight, please refer to the most recent AABB Technical Manual.

Compliance Statement B: For laboratory developed tests not using a RUO kit, and for FDA approved, cleared or 510(k) exempt assays with alterations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.


This test should only be used to detect and quantify the extent of fetomaternal hemorrhage, in pregnant or post-partum 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 (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