Kell K/k Antigen (KEL) Genotyping
0051644
Ordering Recommendation
Assess risk for alloimmune hemolytic disease of the newborn or hemolytic transfusion reaction. Test may be ordered for parental or fetal genotyping.
Mnemonic
KEL
Methodology
Polymerase Chain Reaction/Fluorescence Monitoring
Performed
Mon, Thu
Reported
2-7 days  
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
  
Collect
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 Remarks): Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). Parental Genotyping: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).  
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
  
Remarks
Maternal specimen is recommended for proper test interpretation if contamination of the fetal specimen from the mother is suspected. Order Maternal Cell Contamination. Patient History Form is available on the ARUP website or by contacting ARUP Client Services.  
Stability
Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Whole Blood or Maternal Cell contamination Specimen:
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable  
Reference Interval
   
Interpretive Data
Background information: Kell K/k Antigen (KEL) Genotyping:
Characteristics:
Fetal orneonatal hemolytic anemia, erythroblastosis and hydrops.
K Allele Frequency
: 9 percent of Caucasians, 2 percent of African Americans; unknown for other ethnic groups.
Inheritance
: Autosomal dominant.
Cause:
Maternal-fetal or transfusion-related K antigen incompatibility.
Polymorphism Tested:
KEL1 and KEL2 alleles of the KEL gene. The KEL1 allele is known as K (c.578C>T; p.Thr193Met) and the KEL2 allele is known as k (common allele). The presence of the KEL1 allele predicts a Kell-positive phenotype.
Clinical Sensitivity
: 99 percent.
Methodology
: Polymerase chain reaction (PCR) and fluorescent monitoring using hybridization probes to detect the c.578C>T polymorphism.
Analytic Sensitivity and Specificity
: 99 percent.
Limitations
: Bloody amniotic fluid samples may give false-negative results because of maternal cell contamination. Diagnostic errors can occur due to rare sequence variations.

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.

This test is performed pursuant to an agreement with Roche Molecular Systems, Inc





See Compliance Statement C: www.aruplab.com/CS
Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
 
Note
 
CPT Code(s)
81479
Components
Component Test Code*Component Chart Name
0051645KEL Specimen
0051646Kell K/k Antigen (KEL) Genotyping
* 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.
Aliases
  • KEL 1 and 2 genotyping
  • Kel1 heterzygosity or homozygosity assay
  • Kell Antigen genotyping