ARUP's Laboratory Test Directory

Kell K/k Antigen (KEL) Genotyping : 0051644
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Time Sensitive
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Informed Consent and Technical Information


Mnemonic: KEL

Ordering Recommendation: Assess risk for alloimmune hemolytic disease of the newborn or hemolytic transfusion reaction. Test may be ordered for parental or fetal genotyping.
Methodology: Polymerase Chain Reaction/Fluorescence Monitoring
Performed: Mon, Thu
Reported: 2-7 days
Specimen Required: 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.

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 (collection to initiation of testing): Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Whole Blood or Maternal Cell contamination Specimen: Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Interpretive Data: Background information: Kell K/k Antigen (KEL) Genotyping:
Characteristics: Fetal or neonatal 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 detected: K (c.578C>T; p.Thr193Met) and k (common allele) in the KEL gene.
Clinical Sensitivity: 99 percent.
Methods: PCR of KEL gene followed by fluorescent monitoring.
Analytic Sensitivity and Specificity: 99 percent.
Limitations: Bloody amniotic fluid samples may give false-negative results because of maternal cell contamination. Specificity may be compromised by primer site mutations.

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



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
CPT Code(s): 81479