Testing of specimens within the United States to determine possible Zika virus infection should be limited to specimens collected from patients meeting CDC’s clinical and epidemiological criteria for testing. As previously indicated, information on clinical signs and symptoms associated with Zika virus infection is available from the CDC. It is important to note that Zika virus infection can cause signs and symptoms similar to those seen in patients with dengue and chikungunya virus infections. In addition, the primary diagnostic specimens recommended by the CDC for Zika virus infection are serum and urine.
In general, the CDC recommends Zika virus testing if any individual has symptoms of Zika and they have lived in or traveled to an area with a risk of Zika virus exposure or if an individual has had sex without a condom with a partner who lives in or traveled to an area with risk of Zika.
For pregnant women, the CDC recommends that Zika testing be performed for individuals with symptoms of Zika as well as for asymptomatic women with possible exposure to the Zika virus because of living in or frequently traveling to an area with a risk of Zika. Also, if a clinician observes Zika-associated abnormalities on an ultrasound or a pregnant woman delivers a baby with birth defects that may be related to Zika, testing for the virus should be done on the pregnant woman, and testing of placental and fetal tissues may also be considered.
For men, the CDC now recommends that men with possible Zika virus exposure who plan to conceive with their partner wait at least three months after symptom onset or their last possible Zika virus exposure before engaging in unprotected sex.
In August 2018, the CDC issued an updated interim guidance for counseling and prevention of sexual transmission of the Zika virus for men. For additional details, please access the following reference link:
In late July 2017, the CDC issued updated guidance for US laboratories testing for Zika virus infection. Under these guidelines, the CDC used the general term nucleic acid test (NAT) as a generic term referring to all molecular tests used to detect Zika viral RNA, including all molecular tests receiving EUA approval by the FDA. As stated previously, most of these approved molecular tests employ the rRT-PCR assay.
These updated guidelines recommend using paired serum and urine as the primary diagnostic specimens for Zika virus testing. If diagnostic testing is conducted on other specimen types, such as whole blood, CSF, or amniotic fluid, then it is required that a patient-matched serum be concurrently obtained for NAT and/or IgM serological testing as appropriate. The updated guidance has recommendations specifically for symptomatic pregnant women as well as symptomatic non-pregnant individuals and asymptomatic pregnant women with possible exposure to Zika. In addition, there are also recommendations for pregnant women with possible exposure to the virus who have a fetus with prenatal ultrasound findings consistent with congenital Zika virus infection.
This course will concentrate on the testing guidelines for pregnant or non-pregnant symptomatic individuals and asymptomatic pregnant women.
For more details on CDC guidance for laboratory testing for the Zika virus, please consult the following reference link:
