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Test Code ZIKAIGM Zika Virus, MAC-ELISA, IgM, Serum

Performing Laboratory



IgM antibody capture ELISA






Reference Values



Test Classification and CPT Coding


Physician Office Specimen Requirements

Container/Tube: Red-top tube or gel-barrier tube

Specimen: 2 mL serum (1 mL serum min.)

Transport Temperature: Refrigerated serum

Computer Interface Code

PDM #  16559533

Useful For

Presumptive (not definitive) evidence of Zika virus infection


Interpretation of Zika MAC-ELISA results must account for the possibility of false-negative and false-positive results. False-negative results can arise from:

a) Specimen collection conducted before IgM has reached detectable levels (typically around 4 days postonset of symptoms).

b) Specimen collection conducted after IgM levels have decreased below detectable levels (typically around 12 weeks postonset of symptoms).

c) Failure to follow the authorized assay procedures.

The most common cause of false-positive results is cross-reactivity with IgM specific for other flaviviruses such as dengue virus. Only limited evaluation of cross-reactivity with flaviviruses or arboviruses has been conducted. No evaluation of cross-reactivity with rheumatoid factor has been conducted. Clinical data indicate cross-reactivity with antidengue virus antibodies is likely. Follow-up testing is necessary to rule out a false-positive result. Confirmation of the presence of anti-Zika IgM requires testing by CDC or a CDC-designated laboratory. The gold-standard method for confirmation of the presence of anti-Zika antibodies is the plaque reduction neutralization test (PRNT).

All Zika testing must be conducted following the CDC-issued Zika laboratory guidance and testing algorithms:

Negative results do not preclude infection with Zika virus and should not be used as the sole basis of a patient treatment/management decision. All results should be interpreted by a trained professional in conjunction with review of the patient's history and clinical signs and symptoms.

This assay is for in vitro diagnostic use under FDA Emergency Use Authorization only and is limited to qualified laboratories designated by CDC.

All specimens should be handled as if infectious. Proper biosafety precautions, including personal protective equipment, must be used when handling specimen materials.

Proper collection, storage and transport of specimens are essential for correct results.

Performance has only been established with the specimen types listed in the Intended Use. Other specimen types are not acceptable for use with this assay.

It should be noted that as of April 2016, any patient whose sample yields positive PRNT results (ie, ≥10) for both Zika and dengue virus is now classified as having a flavivirus infection. This virus infection is only specified if one result is positive and the other negative. The former fourfold difference to identify the infection has been shown to be incorrect in a number of instances and has now been abandoned for Zika diagnosis only.