Ordering Recommendation

Use to evaluate stiffness, spasms, hyperekplexia, limb rigidity, myoclonus, or limb dystonia in the presence or absence of encephalopathy. For individuals who present with a broader phenotype suggestive of immune-mediated movement disorder, refer to Autoimmune Movement Disorder Panel, Serum (3006206).

Testing in both serum and CSF is recommended to maximize diagnostic yield; refer to Autoimmune Stiff-Person Disorders, CSF (3006235) for CSF testing.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation



Serum separator tube (SST)

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer three 1 mL serum aliquots to ARUP standard transport tubes. (Min: 0.5 mL/aliquot)

Storage/Transport Temperature


Unacceptable Conditions

Amniotic fluid, ocular fluid, peritoneal fluid, synovial fluid, CSF, or plasma. Contaminated, hemolyzed, icteric, or lipemic specimens.


After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 30 days (avoid repeated freeze/thaw cycles)


Semi-Quantitative Cell-Based Indirect Fluorescent Antibody/Qualitative Immunoblot/Semi-Quantitative Enzyme-Linked Immunosorbent Assay (ELISA)




3-10 days

Reference Interval

Test Number
Reference Interval
  Neuronal Antibody (Amphiphysin) Negative
  Glutamic Acid Decarboxylase Antibody 0.0-5.0 IU/mL
  DPPX Ab IgG CBA-IFA Screen, Serum Less than 1:10

Interpretive Data

Refer to report.

Compliance Category

Laboratory Developed Test (LDT)


If DPPX antibody IgG by IFA is positive, then titer will be added. Additional charges apply.

Hotline History


CPT Codes

86341; 84182; 86255; if reflexed, add 86256


Component Test Code* Component Chart Name LOINC
0051709 Neuronal Antibody (Amphiphysin) 94385-2
2001772 Glutamic Acid Decarboxylase Antibody 56540-8
3004361 DPPX Ab IgG CBA-IFA Screen, Serum 94676-4
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • DPPX
  • Amphiphysin
  • Dipeptidyl aminopeptidase-like protein 6
  • dystonia
  • GAD65
  • Glutamic acid decarboxylase
  • hyperekplexia
  • PERM
  • Progressive encephalomyelitis
  • Progressive encephalomyelitis with rigidity and myoclonus
  • rigidity
  • spasms
  • Spinal interneuronitis
  • SPS
  • Stiff man
  • Stiff person
  • Stiff-man
  • Stiff-person
  • Stiff-person syndrome
Autoimmune Stiff-Person Disorders, Serum