Expected Turnaround Time
14 - 28 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Specimen Requirements
Specimen
Whole blood
Volume
4 mL
Minimum Volume
1 mL
Container
Lavender-top (EDTA) tube
Collection
Draw blood into EDTA tube.
Storage Instructions
Ship ASAP, but stable up to 5 days post-collection at room temperature. Do not freeze.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 5 days |
Refrigerated | 5 days |
Frozen | Do not freeze |
Causes for Rejection
Frozen blood EDTA tube
Test Details
Use
Spinocerebellar ataxias (SCAs), and episodic ataxias are the most common types of autosomal dominant cerebellar ataxias (ADCAs). SCAs are numbered based upon their time of identification. SCA3 is the most common type of SCA worldwide, followed by SCA2, SCA1, and SCA6. Some of the complicated forms have not been given a SCA number, like Dentatorubral Pallidoluysian Atrophy (DRPLA). Anticipation can be observed in the autosomal dominant ataxias in which CAG trinucleotide repeats occur. Anticipation results from expansion in the number of CAG repeats with transmission of the gene to subsequent generations. Most ADCAs have an overlap in clinical presentation, which makes it hard to differentiate. The most frequent clinical symptoms in all ADCAs are progressive adult-onset gait ataxia (often with hand dysmetria), and dysarthria associated with cerebellar atrophy. The episodic ataxias are characterized by periods of unsteady gait and often associated with nystagmus or dysarthria. Myokymia, vertigo, or hearing loss may occur in some of the subtypes. Permanent ataxia and even cerebellar atrophy may result late in the disease course.
Limitations
Maximum reportable sizing: 65 repeats.
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Repeat-Primed PCR (QP-PCR)
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