Ordering Recommendation

Aids in diagnosis of limbic encephalitis. May be used to monitor treatment response in individuals who initially test positive for DPPX antibodies. The presence of DPPX antibodies may be associated with hyperexcitability, pleocytosis, and frequent diarrhea. DPPX encephalitis may be paraneoplastic; hematologic malignancies are reported in a subset of patients.

Mnemonic

DPPX SER

Methodology

Semi-Quantitative Indirect Fluorescent Antibody

Performed

Wed

Reported

1-8 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Serum separator tube.

Collect

Separate serum from cells within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL)

Specimen Preparation
Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

CSF or plasma. Contaminated, hemolyzed, or severely lipemic specimens.

Remarks
Stability

After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 30 days (avoid repeated freeze/thaw cycles)

Reference Interval

Effective November 15, 2021
Less than 1:10

Interpretive Data

Anti-DPPX IgG antibody is found in a subset of patients with autoimmune encephalitis and may occur with or without associated tumor. Decreasing antibody levels may be associated with therapeutic response; therefore, clinical correlation must be strongly considered. A negative test result does not rule out a diagnosis of autoimmune limbic encephalitis.

This indirect fluorescent antibody cell-based assay (CBA) utilizes dipeptidyl aminopeptidase-like protein 6 (DPPX) transfected cells for the detection of the DPPX IgG antibody.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Note

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

Hotline History

N/A

CPT Codes

86255; if reflexed, add 86256

Components

Component Test Code* Component Chart Name LOINC
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.

Aliases

Dipeptidyl Aminopeptidase-Like Protein 6 (DPPX) Antibody, IgG by IFA With Reflex to Titer, Serum