Stiff-Person Spectrum Disorders Evaluation, Serum (Sendout)

Useful For:

• Evaluating patients with suspected stiff-person syndrome (classical or focal forms, such as stiff-limb or stiff-trunk) and progressive encephalomyelitis with rigidity and myoclonus using serum specimens

Testing Algorithm:

• If the indirect immunofluorescence assay (IFA) pattern suggests amphiphysin antibody, then amphiphysin immunoblot and amphiphysin IFA titer will be performed at an additional charge.
• If the dipeptidyl-peptidase-like protein-6 (DPPX) cell bound assay is positive, then DPPX antibody IFA titer will be performed at an additional charge.

Patient Preparation: This test should not be requested for patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held 1 week and assayed if sufficiently decayed or canceled if radioactivity remains.

Ordering Requirements: Laboratory Medicine Resident approval is required.

Ordering Guidance: GAD65 Ab Assay (Sendout) [RGD65] is the recommended first-line test for Stiff-Person Syndrome. If panel testing is desired after a negative GAD65 Antibody result, submit a LADDON (Lab Add On) request for OLTG #1108/Mayo Test SPPS and specify that testing should be added to the sample at Mayo Clinic Laboratories. Specimens are stored at Mayo for up to 28 days.

Reference Ranges:

Note: Includes reference values for panel tests only.

Interpretation: Seropositivity supports the clinical diagnosis of stiff-person spectrum disorder (classical stiff-person, stiff-limb, stiff-trunk, or progressive encephalomyelitis with rigidity and myoclonus). A paraneoplastic basis should be considered.

6 mL blood in RED top tube

Also Accepted: GOLD SST

Outside Laboratories: Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum while awaiting shipment. Ship sample with a cold pack.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, lipemia, or icterus.

Centrifuge sample and transfer serum to a separate plastic vial.

Login: SEND1-;REFRIG

• RSNDT1: MAYO
• RSTYP1: SRM
• RTSRQ1: ;Stiff Person Spectrum Disorders Evaluation, Serum (Mayo Test SPPS)

Sendouts:

• Order Mayo Test: SPPS

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, lipemia, or icterus.