With the number of mosquito-borne Zika infections in Miami-Dade County rising almost daily, including seven more cases confirmed by state health officials on Thursday, Florida Gov. Rick Scott said this week that the federal Centers for Disease Control and Prevention will be sending reinforcements to help speed up test results for the virus.
An increased demand for diagnostic screenings, triggered by Scott’s Aug. 3 mandate that all pregnant women in Florida receive free and unlimited Zika testing at state health departments, has translated into long waits — in some cases as much as five weeks — for results.
“Patients are worried and they want answers, and they need to know,” said Ellen Schwartzbard, an obstetrician with South Miami Hospital, who said she has at least 20 patients who have been waiting five weeks for Zika test results.
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“My goal is to take care of my patients the best way I can,” she said, “and right now the Department of Health is making that really difficult.”
Schwartzbard said she has begun to advise patients that private labs can turn around their Zika tests faster. But she worries for her patients who are awaiting Zika test results in order to make potentially life-changing choices.
“If a patient is going to use this information to make a decision,” she said, “for example to determine when she’s going to terminate her pregnancy, you’re not going to do a test at 20 weeks if you’re not going to find out until after 24 weeks, which is the final gestation after which you can terminate a pregnancy in the state of Florida.”
When CDC performs testing, results will typically be sent to the state or local health department within three weeks after a specimen is received. Reporting times for test results may be longer during summer months or when arbovirus activity increases.
At Jackson Memorial Hospital, the flagship for Miami-Dade’s publicly funded system of hospitals and clinics, the chief pathologist also attributed a spike in testing to the governor’s mandate, said David Andrews, a University of Miami Health System physician who oversees pathology laboratories for Jackson Memorial.
Results can take four weeks or longer, Andrews said. He added that the hospital has sent about 1,100 to 1,200 specimens for Zika testing at the state’s Bureau of Public Health Labs.
Last week, he said, Jackson Memorial was still waiting for the results of 800 to 900 specimens. With “aggressive intervention,” Andrews said, about 300 results came back within two days.
“The backlog was on the paperwork and administrative side, to me reflecting a state of them being overwhelmed,” Andrews said. “These are specimens that had been tested, that we didn’t have results on but that had been tested. ... Why do we have this back up of the results that can’t be sent out?”
State health officials say they are working with doctors and hospitals to ensure faster delivery of results that can be communicated to patients, especially in Miami-Dade, the only place in the nation with active spread of Zika by mosquitoes — in a section of Miami’s Wynwood neighborhood and a 1.5-square-mile area of Miami Beach.
“We continue to work to improve and make the process more efficient,” Mara Gambineri, a health department spokeswoman, said in a written statement. “The department has been meeting with area hospitals on this issue and we have already seen improvements. Additional lab support from the CDC will help ensure tests are conducted and results are delivered to individuals efficiently.”
Why do we have this back up of the results that can’t be sent out?
Dr. David Andrews, pathology director for Jackson Memorial Hospital
The CDC is sending seven people to Florida to support testing and lab functions, according to Scott’s announcement, which noted that the governor requested the federal agency’s help in August.
This year, Florida’s public labs have conducted Zika tests for more than 7,117 people statewide, including at least 2,262 pregnant women, according to state officials.
The state has 5,094 tests for active Zika and 8,516 for Zika antibodies. Three of Florida’s public labs — in Jacksonville, Tampa and Miami — are performing tests, Gambineri said.
In September, she said the three labs have a daily capacity to conduct about 150 tests for active Zika and 130 for antibodies. She said the health department receives about 225 specimens each day.
Gambineri said Florida also contracted with a private laboratory, LabCorp, on Aug. 5 to conduct additional Zika testing for the health department. But she could not provide the number of Zika tests performed by LabCorp since the company came on board.
“It can take time to compile the info as the labs are very busy,” Gambineri said in an email.
With an average of 220,000 births a year in Florida from 2013 to 2015, according to state counts, Andrews, the pathologist for Jackson Memorial, said the state’s lab capacity struck him as too low to meet demand.
“We’re a big state,” he said. “How many pregnant women?”
220,000 Average annual number of births in Florida
Part of the reason for the backlog is that, for most people, confirming a Zika diagnosis requires a series of tests to confirm the virus and to rule out other similar viruses, such as dengue. Most people, Andrews said, have to provide three specimens: two vials of blood and one of urine.
The urine sample and one of the blood samples typically are screened for an active case of Zika through a test that can detect the virus for up to 21 days after onset of symptoms. According to state guidance, the turnaround time for that test — known as a PCR test — once a sample is received at a Florida lab is 24 to 48 hours.
To detect the virus more than 21 days since the onset of symptoms, a blood test — called an IgM test — is administered. It can show whether the body has developed an immune response or antibodies to Zika for about 12 weeks after symptoms began.
Once a blood sample is received at a state lab, the turnaround time is typically three to five days, according to the health department, but requires additional testing — such as ruling out dengue — that might take several weeks.
Patients that are PCR negative and IgM positive may face the longest waits, Andrews said, because their samples may have to be sent for a specialized test that only the CDC conducts, called a plaque reduction neutralization test. A total of 174 tests in Florida have been sent to the CDC for the more specialized analysis, the state said.
“It’s like a research test that involves culturing the virus in a specialized lab,” Andrews said. “That's a minimum of four weeks to turn around.”
Zika infections reported in Florida as of Sept. 15
Number of Cases
Total cases not involving pregnant women
. . .
. . .
Cases involving pregnant women regardless of symptoms*
* Counties of pregnant women are not disclosed
** Does not include infections to out-of-state residents.
Source: Florida Department of Health
Potential Zika Testing Outcomes
Additional Action Steps Before Case Determination (results must be reviewed with case investigation materials)
No additional steps
Case investigation conducted
Case investigation conducted
Recent flavavirus infection
Must rule out other recent infections by related viruses (dengue) in the past several months. This requires additional testing which can take several weeks. Case investigation is conducted.
Source: Florida Department of Health