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Test ID: FFRWB Friedreich Ataxia, Frataxin, Quantitative, Blood

Reporting Name

Frataxin, Quant, WB

Useful For

Diagnosing individuals with Friedreich ataxia in whole blood specimens


Monitoring frataxin levels in patients with Friedreich ataxia


This test is not useful for carrier detection.

Specimen Type

Whole blood

Necessary Information

Provide a reason for testing with each specimen.

Specimen Required

Collection Container/Tube: 

Preferred: Lavender top (EDTA)

Acceptable: Green top (sodium or lithium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 2 mL

Specimen Minimum Volume

1.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Frozen (preferred) 70 days
  Ambient  70 days
  Refrigerated  70 days

Reference Values

Pediatric (<18 years) normal frataxin: ≥19 ng/mL

Adults (≥18 years) normal frataxin: ≥21 ng/mL

Day(s) Performed

Twice per month, Thursday

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
FFRWB Frataxin, Quant, WB 80979-8


Result ID Test Result Name Result LOINC Value
32253 Reason for Referral 42349-1
32254 Method 85069-3
32255 Frataxin 80979-8
32256 Interpretation 59462-2

Clinical Information

Friedreich ataxia (FA) is an autosomal recessive disease affecting approximately 1:50,000 individuals in the white population. The disease is clinically characterized by progressive spasticity, ataxia, dysarthria, absent lower limb reflexes, sensory loss, and scoliosis. Cardiac involvement occurs with the development of myocardial fibrosis due to mitochondrial proliferation and loss of contractile proteins. It tends to be correlated with the clinical neurologic age of onset and the GAA triplet repeat length, but not the duration of disease or the severity of neurologic symptoms. Although most individuals begin experiencing initial symptoms between 10 and 15 years of age, atypical late-onset forms with initial symptoms presenting after age 25 do occur.


FA is caused by variants in the FXN gene encoding a mitochondrial protein, frataxin. Variants in this gene lead to a reduced expression of frataxin, which causes the clinical manifestations of the disease. Approximately 98% of individuals with FA have a homozygous expansion of the GAA trinucleotide repeat in intron 1 of FXN. The remaining 2% of FA patients have the trinucleotide expansion on 1 allele and a point alteration or deletion on the second allele. Normal alleles contain between 5 to 33 GAA repeats. Disease-causing alleles typically range from 66 to 1700 repeats, though the majority of individuals with FA have repeats ranging from 600 to 1200.


Historically, FA has been diagnosed by use of a DNA-based molecular test to detect the presence of the GAA expansion. Unfortunately, testing for the triplet repeat expansion will miss those patients with point alterations or deletions. Moreover, a molecular-based analysis is not able to effectively monitor treatment. In contrast, a protein-based assay measuring concentration of frataxin is suitable for both diagnosis as well as treatment monitoring in individuals with FA.


Normal results (≥19 ng/mL for pediatric and ≥21 ng/mL for adult patients) in properly submitted specimens are not consistent with Friedreich ataxia.


For results outside the normal reference range an interpretative comment will be provided.

Clinical Reference

1. Deutsch EC, Oglesbee D, Greeley NR, Lynch DR: Usefulness of frataxin immunoassays for the diagnosis of Friedreich ataxia. J Neurol Neurosurg Psychiatry. 2014 Sep;85(9):994-1002

2. Delaytycki MB, Bidichandani SI: Friedreich ataxia pathogenesis and implications for therapies. Neurobiol Dis. 2019;Dec:132:104606. doi: 10.1016/j.nbd.2019.104606

3. Boehm T, Scheiber-Mojdehkar B, Kluge B, et al: Variations of frataxin protein levels in normal individuals. Neurol Sci. 2011 Apr;32(2):327-330. doi: 10.1007/s10072-010-0326-1

4. Hanson E, Sheldon M, Pacheco B, et al: Heart disease in Friedreich's ataxia. World J Cardiol. 2019;11(1):1-12

Report Available

14 to 30 days

Method Name



1. 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:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602) .

3. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Neurology Specialty Testing Client Test Request (T732)

-Biochemical Genetics Test Request (T798)

Mayo Clinic Laboratories | Genetics and Pharmacogenomics Catalog Additional Information: