This page contains information on Zika virus testing and
reporting for suspect cases residing in Los Angeles
County. It also contains information for notifying
Public Health for special cases. If you need to report
or consult on a case residing outside Los Angeles County,
click here for a listing of
other Health Departments.
Nile Virus and Other Arboviral Diseases Report: November
Zika Virus Testing Eligibility
Health Advisory: Updated Guidance for Health Care
Providers Caring for Pregnant Women with Zika Virus
Preventing Zika Virus Infection and its
Consequences: Update and Guidance for Clinicians
[1 credit CME available]
Zika Virus Testing and
Use the section headings below to navigate to the
pertinent sections of this page:
Indications for Zika Virus Testing and Notification
Obtain clinical and travel history
Providers who suspect a case of Zika virus
infection should obtain a relevant clinical history including previous
dengue/chikungunya/West Nile virus
infection, travel history, Japanese encephalitis virus/yellow
fever/tickborne encephalitis vaccination history, as well as the results
of relevant diagnostic tests, if performed (e.g., ultrasound imaging, TORCH serology panel,
West Nile virus serology, dengue serology, chikungunya serology).
Visit the CDC website for an updated list of countries with active Zika virus transmission.
Testing at Los
Angeles County Public Health Laboratories (PHL)
The PHL offers access to all recommended Zika and related arbovirus testing
services. Public Health is able to complete all required screening and
confirmatory testing for Zika as well as dengue and chikungunya. Some of this
testing is sent to the California State laboratory and/or CDC.
In order for specimens to be processed for Zika testing, the PHL
Zika Virus Testing and Report Form must be completed. Failure to complete
required fields on the requisition forms will result in specimen rejection or
delayed testing. The form includes a two page reporting and test requisition
form as well as the specimen requirements and submission instructions found
below. A separate test requisition form must be submitted for each specimen
Click here to access the Zika Virus Testing and Report Form.
Specimen Requirements for Zika Testing
Note: requested sample volumes are for adults.
* Specimens must be received within 24 hours of collection.
**Do not use glass vacutainer tube for blood collection. Do not use tubes that contain anti-coagulants.
***To optimize evaluation of possible Zika virus
infection on fetal tissues, please provide both formalin
fixed and unfixed tissues. If it is not possible to
provide both types of tissues, prioritize formalin fixed
tissues. For additional information regarding collection
of fetal or infant tissues, please contact the Public
Health Laboratories for guidance.
Instructions for test requests
Samples submitted with incomplete intake information, incomplete patient history, incomplete or discrepant patient sample identifiers and labeling information, or incomplete test request forms will not be tested.
Provider may be required to complete additional forms for receiving results by fax if not currently a client of the Los Angeles County PHL.
Convalescent serum or an additional serum sample may be requested depending on
- Download and complete the required information for
Zika Virus Testing and Report Form. Separate testing forms (both pages 1 and 2) must accompany each specimen type.
- The following information must be included on the form:
- Facility/Submitter name, address, phone, and fax
- Requesting provider name (Last, First) and contact information to enable reporting of results.
- Patient name or unique patient identifier
- Patient sex
- Patient date of birth
- Test(s) to be performed
- Specimen source
- Date and time of specimen collection
- If the patient or provider are unable to obtain phlebotomy services,
contact the Los Angeles Acute Communicable Disease Control Program (ACDC) for assistance, approval and referral to a Los Angeles County Public Health Clinic.
- Specimens must be labeled with the following information:
- Patient name (Last, First)
- Date of Birth
- Collection Date and Collection Time
Specimen processing and packaging
Proper storage and transport conditions preserve analyte integrity within the sample. Leaking specimens will also be rejected.
- Clinics able to process specimens may centrifuge blood and transfer serum to a separate, sterile labeled tube.
- Samples must be sent to PHL as soon as possible and within 24 hours of collection.
- Each specimen type must come with its own test request form
- Each specimen must be packaged using individual biohazard specimen transport bags.
At this time, laboratory samples for Zika testing should not be sent directly to the California State Department of Public Health or the Centers for Disease Control.
Send samples to the
Los Angeles County Public Health Laboratories as soon as possible and within 24 hours of collection.
Los Angeles County Public Health Laboratories
12750 Erickson Avenue
Downey, CA 90242
Specimen transport conditions must be followed or sample will be rejected.
If the provider does not have access to courier services, PHL will help to arrange for sample pick up. Courier arrangements are made by calling PHL Central Accessioning Unit at 562-658-1460.
For consultation regarding appropriate testing, providers should contact ACDC
- Call 213-240-7941 during business hours.
- Call 213-974-1234 after hours, weekends, or holidays and ask the County Operator (option 8) for the Public Health Physician on call.
For questions regarding specimen collection or laboratory interpretation, providers should contact PHL.
- Call 562-658-1330 during business hours.
- Call 213-974-1234 after hours, weekends, or holidays and ask the County
Operator (option 8) for the Public Health Laboratories Director.
at Commercial Laboratories
reverse-transcription polymerase chain reaction (rRT-PCR) molecular assays are
now becoming available at commercial laboratories.
These tests are generally recommended for symptomatic patients as per the
indications listed in the
and Notification table (shown above).
Appropriate samples for rRT-PCR testing are test
dependent. In general, the specimen types include serum
samples collected <7 days and urine samples collected
<14 days after symptom onset. Urine should
always be collected with a patient-matched serum
specimen for rRT-PCR testing.
A positive result in either specimen type provides
evidence of Zika virus infection.
Negative PCR results do not rule out Zika infection and
require a subsequent serum sample for Zika IgM antibody
Currently, commercial laboratories
have Zika IgM enzyme-linked immunosorbent assay (ELISA)
and confirmatory serologic testing (plaque reduction
neutralizing test or PRNT) that are recommended if the
PCR testing is negative. Molecular testing on tissue
samples, CSF, and amniotic fluid are not currently
available at commercial laboratories. For this reason,
if a commercial testing laboratory is used for PCR
testing, it is recommended that:
- Providers are familiar with the laboratory-developed/Emergency Use Authorized test performed at the commercial laboratory and corresponding specimen requirements which may differ from that performed at Public Health Laboratories.
Providers assure that the commercial laboratory can perform PCR testing at least on both urine and serum specimens.
Providers retain and store in a refrigerator (2-8°C) an adequate number of blood specimens for patient's serum to perform subsequent Zika IgM ELISA testing through public health if the PCR is negative.
For specimens that are 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.
Note: Facilities that do not have the capability to process and adequately store serum samples for subsequent antibody testing, should contact PHL for assistance at 562-658-1330/1300.
If a commercial laboratory is used for Zika PCR testing, providers must report all positive Zika tests by submitting a
Confidential Morbidity Report.
The Los Angeles County PHL will continue to offer access to Zika and other related arbovirus testing services (see
Testing at Los Angeles County Public Health Laboratories section above).
For additional information on commercial laboratory testing from CDC, see Health Update:
Recommendations for Subsequent Zika IgM
Antibody Testing (6/21/16).
Page last updated 6/23/16.