Kell K/k (KEL) Antigen Genotyping
Ordering Recommendation

Assess risk for alloimmune hemolytic disease of the fetus and newborn (HDFN) or hemolytic transfusion reaction due to KEL*01 (K) or KEL*02 (k) alloimmunization. May be ordered for parental or fetal genotyping.

Polymerase Chain Reaction/Fluorescence Monitoring
3-10 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Fetal Genotyping: Amniotic fluid OR two T-25 flasks at 80 percent confluency of cultured amniocytes. If the client is unable to culture amniocytes, this can be arranged by contacting ARUP Client Services at (800) 522-2787.
WITH Maternal Cell Contamination Specimen (see Note): Lavender (K2EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).
Parental Genotyping: Lavender (K2EDTA), Pink (K2EDTA). 
Specimen Preparation
Amniotic Fluid: Transport 10 mL unspun fluid. (Min: 5 mL)
Cultured Amniocytes:
Fill flasks with culture media. Transport two T-25 flasks at 80 percent confluency of cultured amniocytes filled with culture media. Backup cultures must be retained the client's institution until testing is complete.
Maternal Cell Contamination Specimen:
Transport 3 mL whole blood (Min: 1 mL)
Whole Blood (Parental Genotyping):
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Amniotic fluid: Room temperature.
Cultured Amniocytes: CRITICAL ROOM TEMPERATURE. Must be received within 48 hours of shipment due to liability of cells.
Whole Blood or Maternal Cell Contamination Specimen: Refrigerated. 
Unacceptable Conditions
Plasma or serum. Specimens collected in sodium heparin tubes. 
Patient History Form is available on the ARUP website or by contacting ARUP Client Services. 
Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Whole Blood or Maternal Cell contamination Specimen:
Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month 
Reference Interval
By report.
Interpretive Data
Background information: Kell K/k (KEL) Antigen Genotyping:
Erythrocyte alloimmunization may result in hemolytic transfusion reactions or hemolytic disease of the fetus and newborn (HDFN).
K Antigen Frequency: 9 percent of Caucasians, 2 percent of African Americans, rare in Asians.
: Co-dominant.
Antigen-antibody mediated red-cell hemolysis between donor/recipient or transferred maternal antibodies.
Polymorphism Tested: Kell blood group KEL*01 (K), KEL*02 (k): c.578C>T, p.Thr193Met. The presence of KEL*01 allele predicts a K positive phenotype.
Clinical Sensitivity
: 99 percent.
: Immucor PreciseType™ HEA Molecular BeadChip which is FDA-approved for clinical testing.
Analytic Sensitivity and Specificity: 99 percent.
: Bloody amniotic fluid samples may give false-negative results because of maternal cell contamination. Rare nucleotide changes leading to altered or partial antigen expression and null phenotypes are not detected by this assay. Patients who have had hematopoietic stem cell transplants may have inconclusive results on this test. Abnormal signal intensities may result in indeterminate genotyping results.

For quality assurance purposes, ARUP Laboratories will confirm the above result at no charge following delivery. Order Confirmation of Fetal Testing and include a copy of the original fetal report (or the mother's name and date of birth) with the test submission. Please contact an ARUP genetic counselor at (800) 242-2787 extension 2141 prior to specimen submission.

Maternal specimen is recommended for proper test interpretation if contamination of the fetal specimen from the mother is suspected. Order Maternal Cell Contamination.
Hotline History
View Hotline History
Component Test Code*Component Chart NameLOINC
3002013KEL GENO Specimen31208-2
3002014KEL Genotype34656-9
* 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.
  • KEL1 and KEL2 genotyping
  • Kel1 heterozygosity or homozygosity assay
  • Kell Antigen genotyping
  • Kell/Cellano genotyping