Kleihauer-Betke Test Synonyms Acid Elution for Fetal Hemoglobin; Fetal Hemoglobin Stain; Fetal-Maternal Hemorrhage Test

Test Includes Staining of a postpartum maternal blood specimen for identification of percentage of fetal cells present

Laboratory Core Laboratory

Request Form Routine Blood Requisition

Phone (212) 305-8600

Availability Daily, 24 hours

Turnaround Time Same day

Special Instructions Collection date and time must be on the requisition.

Specimen Blood

Volume 5 mL

Minimum Volume 2 mL

Container Lavender top (EDTA) tube

Collection Routine venipuncture

Storage Instructions Blood must be delivered to laboratory within 6 hours of collection.

Causes for Rejection Clotted or hemolyzed specimen, less than minimum amounts, longer than 6 hours since collection

Reference Range Normal adults: Hb F cells <0.4%

Use This test is ordered if the fetal screen test performed by the Transfusion Service is positive. In nonobstetrical cases, this procedure is used to assist in the diagnosis of thalassemia major, thalassemia minor, and hereditary persistent fetal hemoglobin (HPFH). In obstetrical cases, this procedure is used to detect the presence of fetal erythrocytes in the mother's circulation.

Methodology Acid elution. After fixation with alcohol, Hb F remains as a precipitate within the cell while Hb A is soluble in citric acid phosphate buffer. The adult RBCs containing little or no Hb F appear as ghosts microscopically.