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Fetal Cells, Kleihauer Betke

Fetal Cells, Kleihauer and Betke, fetal hemoglobin, hemoglobin F, acid elution slide test, acid elution for fetal hemoglobin

Test Codes

EPIC: LAB474

Department

Hematology

Specimen Collection Criteria

Collect (preferred specimen): One 4.0 mL Lavender-top K₂EDTA tube. (Minimum: 2.0 mL)
Also acceptable: One Lavender-top K ₂EDTA Microtainer^®. (Minimum: 300.0 mcL)
One Pink-top K₂EDTA Microtainer^®. (Minimum: 200.0 mcL)

Physician Office/Draw Specimen Preparation

Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport. Room temperature (20-26°C or 68-78.8°F) is acceptable for a maximum of 2 hours.

Preparation for Courier Transport

Transport: Whole blood or capillary blood refrigerated (2-8°C or 36-46°F). (Minimum: 2.0 mL whole blood or 300 mcL capillary blood)

Rejection Criteria

• Specimens containing clots.
• Insufficient volume.
• Frozen specimens.
• Centrifuged specimens.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 48 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 5 days

Laboratory

Dearborn Blood Bank Laboratory
Royal Oak Hematology Laboratory
Troy Hematology Laboratory

Performed

Dearborn & Troy: 
Sunday – Saturday, 24 hours a day. Results available within 24 hours. 

Royal Oak:
Monday – Friday (before 3:00 pm), Saturday (before 1:30 pm) in Royal Oak Flow Cytometry. Results available within 4 hours. 

Saturday (after 1:30 pm), Sunday, and Holidays in Royal Oak Hematology Laboratory. Results available within 8 hours.

EC requests are trauma cases that define a possible fetal bleed. Afternoon, midnight and weekend requests from EC will be processed immediately.

Reference Range

Less than or equal to 0.30%.

Test Methodology

Flow Cytometry or Kleihauer-Betke.

Interpretation

Normal adult blood will contain less than 0.01% Hb F cells. Acceptable results for OB patients is less than 0.30%. In full term newborns, fetal cells are about 90%.

Clinical Utility

Fetal blood may enter into the maternal circulation during pregnancy, at delivery, during abortion, and as a result of trauma. When a Rh negative mother is carrying a Rh positive fetus the amount of fetal erythrocytes present in the maternal circulation determines the dose of Rh immune globulin that should be administered to the mother. This assay aids in determining the appropriate dose of Rh immune globulin that should be administered to the mother.

CPT Codes

85460
LOINC: 75373-1

Contacts

Last Updated

9/12/2025