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Test ID KCNN4 KCNN4 Full Gene Sequencing, Varies

Necessary Information

The following information is required on patient information or test request form:

1. Clinical diagnosis

2. Pertinent clinical history (submit CBC results and relevant clinical notes)

3. Differentials based on clinical or morphologic presentation

4. Date of collection

5. Specimen type, whole blood or extracted DNA

Specimen Required

Submit only 1 of the following specimens:



Specimen Type: Peripheral blood


Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Green top (heparin)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as blood.

Specimen Stability Information: Ambient 14 days (preferred) or Refrigerated ≤30 days



Specimen Type: Extracted DNA from whole blood

Container/Tube: 1.5- to 2-mL tube with indication of volume and concentration of DNA

Specimen Volume: Entire specimen

Collection Instructions: Label specimen as extracted DNA from blood and provide indication of volume and concentration of the DNA

Specimen Stability Information: Frozen/Refrigerate/Ambient ≤30 days


1. Metabolic Hematology Next-Generation Sequencing (NGS) Patient Information is required, see Special Instructions.

2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

3. If not ordering electronically, complete, print, and send a Benign Hematology Test Request (T755) with the specimen

Useful For

Genetic confirmation of a dehydrated hereditary stomatocytosis (DHSt) 2/hereditary xerocytosis diagnosis with the identification of an alteration known or suspected to cause disease in the KCNN4 gene


Second-tier testing for patients in whom previous targeted gene variant analyses were negative for a specific RBC membrane disorder


Establishing a diagnosis of a hereditary RBC membrane disorder, allowing for appropriate management and surveillance of disease features based on the gene involved, especially if splenectomy is a consideration

Genetics Test Information

This test detects pathogenic alterations within the KCNN4 gene which are associated with hereditary stomatocytosis.


The gene target for this test includes the following:

Gene name (transcript): KCNN4 (GRCh37 (hg19) NM_002250)

Chromosomal location: chr19q13.31


This test should be used as an adjunct to abnormal RBC membrane studies.

-Variants in KCNN4 are associated with rare red cell membrane disorder dehydrated hereditary stomatocytosis, which causes chronic hemolytic anemia.

-Informative protein studies (eg, osmotic fragility, ektacytometry) and peripheral blood findings, correlated with the patient clinical history, should be performed prior to genetic testing.

Method Name

Polymerase Chain Reaction (PCR) Amplification /Sanger Sequence Analysis

Reporting Name

KCNN4 Full Gene Sequencing, V

Specimen Type


Specimen Minimum Volume

Blood: 1 mL
Extracted DNA: 50 mcL at 50 ng/mcL concentration

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Friday

Report Available

8 to 10 weeks

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
KCNN4 KCNN4 Full Gene Sequencing, V 98954-1


Result ID Test Result Name Result LOINC Value
607810 Interpretation 82939-0
607811 Signing Pathologist 19139-5

NY State Approved