ARUP's Laboratory Test Directory

California Encephalitis Antibody, IgG by IFA, Serum : 0050508

Mnemonic: CALIF

Methodology: Semi-Quantitative Indirect Fluorescent Antibody
Performed: Tue, Fri
Reported: 1-5 days
Specimen Required: Collect: Serum separator tube.

Specimen Preparation: Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.05 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimens plainly as acute or convalescent.

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Contaminated, hemolyzed, severely lipemic specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
Less than 1:16
Interpretive Data: A positive result for IgG may suggest current or past infection. La Crosse virus is related to viruses within the California Encephalitis Group and, generally, is reactive with antibody to other viruses within this group.
Note: Serum specimens drawn within the first two weeks after onset are variably negative for IgG antibody and should not be used to exclude the diagnosis of arboviral disease.  Seroconversion between acute and convalescent sera is considered strong evidence of recent infection.  The best evidence for infection is a significant change (fourfold difference in titer) on two appropriately timed specimens, where both tests are done in the same laboratory at the same time.
CPT Code(s): 86651
Cross References: Encephalitis Antibody (California Encephalitis Antibody, IgG by IFA, Serum), Encephalitis, La Crosse (California Encephalitis Antibody, IgG by IFA, Serum), La Crosse Encephalitis (California Encephalitis Antibody, IgG by IFA, Serum)