Ordering Recommendation

For evaluation of optic neuritis, acute myelitis, spinal cord lesions, or autoimmune encephalitis.

Mnemonic
AQP4 R
Methodology

Semi-Quantitative Enzyme-Linked Immunosorbent Assay/ Semi-Quantitative Indirect Fluorescent Antibody

Performed

Tue, Thu

Reported

1-6 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Serum Separator Tube (SST).

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

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

Remarks
Stability

After separation from cells: Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles)

Reference Interval
Test Number
Components
Reference Interval
2003036 Aquaporin-4 Receptor Antibody Effective October 3, 2016
Negative 2.9 U/mL or less
Positive 3.0 U/mL or greater

2013320 Aquaporin-4 Receptor Antibody, IgG by IFA with Reflex to Titer, Serum Less than 1:10

Interpretive Data

Approximately 75 percent of patients with neuromyelitis optica (NMO) express antibodies to the aquaporin-4 (AQP4) receptor.  Diagnosis of NMO requires the presence of longitudinally extensive acute myelitis (lesions extending over 3 or more vertebral segments) and optic neuritis.  While absence of antibodies to the AQP4 receptor does not rule out the diagnosis of NMO, presence of this antibody is diagnostic for NMO.

Compliance Category

FDA

Note

If AQP4 antibody IgG by ELISA is positive, then AQP4 antibody IgG by IFA will be added. If AQP4 antibody IgG by IFA is positive, then an AQP4 antibody IgG titer will be added. Additional charges apply.

Hotline History
N/A
CPT Codes

83516; if reflexed, add 86255; if reflexed, add 86256

Components
Component Test Code* Component Chart Name LOINC
2003121 Aquaporin-4 Receptor Antibody 68548-7
* 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
Aquaporin-4 Receptor Antibody by ELISA with Reflex to Aquaporin-4 Receptor Antibody, IgG by IFA