ACL has developed and implemented Zika Testing on July 20th . ACL recommend that all pregnant patients get follow up molecular and serologic tests rather than delaying our results.Testing Plan
This algorithm pertains to women living in the Chicago area (living in an area without active Zika virus transmission).
1. Women with suspected ZIka virus exposure (as defined by CDC guidelines) will have the following samples collected: urine, serum, and plasma.
- All three specimens will be obtained and stored for testing or possible future testing.
- ACL will only bill for the indicated test which was performed.
2.For women with or without symptoms who present <2 weeks from symptom onset or possible exposure:
a.Physicians should order:
- MQBPNL rRT-PCR (Zika, Dengue, Chikungunya testing which is run on plasma and urine samples)
- MBABPN serology (Zika IgM/IgG, Dengue IgM/IgG, Chikungunya IgM/IgG which is run on plasma samples)
b. ACL will test plasma and urine with MQBPNL rRT-PCR.
c. Positive Zika virus rRT-PCR will be reported as a recent Zika virus infection. Patient’s pregnancy will be managed as per current recommendations for Zika virus infection. MBABPN serology will be cancelled and credited by ACL. Per IDPH recommendations, positive serum samples will be sent to state lab for correlation.
d. Negative Zika virus rRT-PCR
- Symptomatic: MBABPN serology will be performed on plasma sample in ACL. Negative results will be considered negative for Zika virus infection. Positive or equivocal serum samples will be sent to IDPH for further testing with PRNT.
- .Asymptomatic: Primary provider to place a new order for MBABPN serology to be obtained 2-12 weeks after exposure. Negative results will be considered negative for Zika virus infection. Positive or equivocal serum samples will be sent to IDPH for further testing with PRNT.
3.For women with or without symptoms who present 2-12 weeks from symptom onset or possible exposure:
- Physicians should order MBABPN serology (Zika IgM/IgG, Dengue IgM/IgG, Chikungunya IgM/IgG which is run on plasma samples)
- Negative Zika virus IgM and positive/equivocal dengue virus IgM: Presumptive dengue virus infection. Sample to be sent to IDPH for further testing with PRNT.
- Positive/equivocal Zika virus IgM and any result for dengue virus IgM: Presumptive recent Zika virus infection. Sample to be sent to IDPH for further testing.
- Negative Zika and dengue virus IgM: Considered to have no recent Zika virus infection.
Pregnancies will be managed as per CDC guidelines based on final testing results (see CDC reference).
The ordering physician/designee provider will need to provide pertinent patient history at the time that the patient presents to ACL for specimen collection.
ACL to determine process for State reporting requirement
Visit IDPH for information regarding any upcoming changes to testing, reporting within the State.
ACL lab sends positive PCR Zika, which is tested by PCR and Zika IgM.
IDPH can’t report positive Zika IgM instead they report as positive for flavivirus (since assay cross-react with Dengue).
IDPH sends to CDC for confirmation by PRNT method to differentiate Zika IgM form Dengue IgM – (average TAT is 4-6 weeks). not sure if withholding results for this long amount time is in the best interest of patients especially if they are pregnant.
ACL recommend that all pregnant patients get follow up molecular and serologic tests rather than delaying our results.
Our report contains very strong language regarding clinical interpretation in PREGNANT patients: “Test results should be used in conjunction with clinical signs and symptoms, epidemiological information and relevant travel history to diagnose Zika virus infection. In case of suspected Zika virus infection in pregnant women, repeated serial testing is recommended; in addition, for patients who are 2-12 weeks post-symptom onset, serologic testing should be performed. Neither the sensitivity nor the specificity of this test is 100%; therefore, negative results
do not rule out Zika virus infection, nor do positive results confirm Zika virus infection. THIS TEST SHOULD NOT BE THE SOLE BASIS FOR ANY PATIENT-MANAGEMENT DECISIONS”