Zika Virus, IgM, Serum

Overview:

Presumptive (NOT definitive) evidence of Zika virus infection. *This test has not been FDA cleared or approved; *This test has been authorized by FDA under an Emergency Use Authorization (EUA) for use by authorized laboratories;*This test has been authorized only for the diagnosis of Zika virus infection and not for any other viruses or pathogens; and *This test is only authorized for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of in vitro diagnostic tests for detection of Zika virus and/or diagnosis of Zika virus infection under section 564(b)(1) of the Act, 21 U.S.C. 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner.

Interpretation of Zika IgM 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 indicatecross-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). Specimens are sent to CDC or a CDC designated State Laboratory for PRNT when results indicate the need based on the most recent algorithm(s). The CDC may refuse to accept specimens for PRNT that do not meet their epidemiologic criteria for PRNT testing. If this occurs you will be notified by the report. Follow up may occur from your state public health laboratory. All Zika testing should be conducted following the CDC Zika laboratory guidance and testing algorithms: http://www.cdc.gov/zika/state-labs/index.html 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 qualifiedlaboratories. 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 specifiedif one result is positive and the other negative. The formerfourfold difference to identify the infection has been shownto be incorrect in a number of instances and has now been abandoned for Zika diagnosis only.