CDC Health Update On Zika Antibody Testing

[niman]

Distributed via the CDC Health Alert Network June 21, 2016, 1140 EDT (11:40 AM EDT)  CDCHAN-00392 CDC Recommendations for Subsequent Zika IgM Antibody Testing Summary Testing for Zika virus infection using real-time reverse-transcription polymerase chain reaction (rRT-PCR) molecular assays is now commercially available. When requesting Zika rRT-PCR testing from a commercial laboratory, providers should be aware that commercial laboratories performing rRT-PCR currently do not also offer Zika IgM enzyme-linked immunosorbent assay (ELISA) or confirmatory serologic testing (plaque reduction neutralization test, or PRNT). Therefore, if possible, providers should store a serum aliquot for subsequent Zika IgM ELISA testing if the rRT-PCR assay is negative. Otherwise, collection of an additional serum sample may be necessary. Recommendations rRT-PCR (molecular) testing should be performed for patients possibly exposed to Zika virus who have symptoms consistent with Zika virus infection Providers who request molecular testing for Zika virus infection from a commercial testing laboratory are advised to retain and store in a refrigerator (2-8°C) an aliquot of the patient’s serum for subsequent Zika IgM ELISA testing if the rRT-PCR is negative For specimens that are rRT-PCR negative from the commercial laboratory and no stored serum specimen is available, another serum specimen should be collected  within 12 weeks of symptom onset for Zika IgM ELISA testing Appropriate samples for molecular testing are serum samples collected Background  Molecular assays for detection of Zika virus RNA are now commercially available under Emergency Use Authorizations (EUAs) issued by the Food and Drug Administration (FDA). CDC recommends molecular testing using rRT-PCR for serum samples collected Currently, commercial laboratories that offer rRT-PCR testing do not provide Zika IgM ELISA testing with PRNT confirmation and have no routine process to forward specimens to another testing laboratory. Therefore, when requesting Zika rRT-PCR testing from a commercial laboratory, providers should retain an aliquot of the serum for Zika IgM ELISA testing if the rRT-PCR testing is negative. Blood should be collected and processed per routine guidelines (collected in a serum separator tube with serum aliquots transferred to new vials), and one of the serum aliquots should be stored in a refrigerator (2-8°Cntil it is known if additional IgM testing is indicated. If a serum aliquot cannot be stored or is not available, but further testing is indicated, a new blood sample should be collected. Serum samples for IgM testing should be collected from patients within 12 weeks of symptom onset. Providers should contact their local health department to discuss IgM testing of stored or newly collected serum from patients who are rRT-PCR negative. For More Information Zika virus specimen collection:  http://www.cdc.gov/zika/hc-providers/body-fluids-collection-submission.html. Interim guidance for Zika virus testing of urine:  http://www.cdc.gov/mmwr/volumes/65/wr/mm6518e1.htm The Centers for Disease Control and Prevention (CDC) protects people's health and safety by preventing and controlling diseases and injuries; enhances health decisions by providing credible information on critical health issues; and promotes healthy living through strong partnerships with local, national, and international organizations.   Categories of Health Alert Network messages: Health Alert         Requires immediate action or attention; highest level of importance Health Advisory   May not require immediate action; provides important information for a specific incident or situation Health Update     Unlikely to require immediate action; provides updated information regarding an incident or situation HAN Info Service Does not require immediate action; provides general public health information ##This message was distributed to state and local health officers, state and local epidemiologists, state and local laboratory directors, public information officers, HAN coordinators, and clinician organizations##