Western Cape healthcare workers have reported waiting up to 10 days for Covid-19 test results - and sources in Gauteng say they are not alone.
Delays in results have left many fearing infected patients, who should otherwise be self-quarantining, could unwittingly be exposing others to the virus.
"The delay is not only being experienced in the Western Cape," says provincial health department spokesperson Nomawethu Sbukwana.
"As the Western Cape - and indeed other provinces - ramp up testing, [the National Health Laboratory Services] are finding it challenging to keep up and process these tests, resulting in a nationwide backlog in the results."
The Western Cape has become the epicentre of South Africa's outbreak of the coronavirus, known as SARS-Cov-2.
Sbukwana said the department had contacted the National Health Laboratory Services (NHLS) to try to ramp up the testing capacity in the province.
It was currently testing about 1 600 people daily for the virus, according to the provincial health department.
The NHLS did not confirm or deny backlogs when Bhekisisa asked, but the lab service did say demand for testing had exceeded its supply.
"The test kits ordered could not be delivered due to logistical challenges that were outside of the suppliers' control," said spokesperson Mzimasi Gcukumana in a statement.
"There were further delays in transporting the supplies due to the lockdown, flight cancellations and the long weekends."
Although Gcukumana said global shortages had also contributed to a scarcity in testing kits, he added the NHLS was working with private and academic laboratories to process samples as quickly as possible.
Meanwhile, Sbukwana said backlogs were a serious threat to efforts to trace close contacts of people diagnosed with the virus.
As samples pile up, results are released in larger batches - meaning teams of community healthcare workers have to try to find more close contacts at any one time.
Clinicians in the Western Cape said it was not uncommon to wait eight days for results to come back, with similar delays having been reported in the Eastern Cape and Gauteng.
Healthcare workers, who spoke to Bhekisisa on condition of anonymity, said they have been told at least one major NHLS Western Cape laboratory has a backlog of almost 5 000 Covid-19 tests. Waiting times for test results, they have been told, were only likely to grow.
Sbukwana did not respond to these allegations.
But sources in the province said the department might be negotiating with at least one private lab to process urgent tests from healthcare workers and hospitalised patients.
Backlog stokes fears that Covid-19 figures could be under-reported
The Eastern Cape and Gauteng did not returned requests for comment at the time of going to print.
But DA spokesperson on health Jack Bloom issued a statement on Friday saying he was alarmed by delays in the province.
"Private laboratories generally provide results within 24 hours but there seems to be a capacity problem with the public tests as I know of cases where the results took as long as seven days," Bloom wrote. "A case in point is the staff member of the Diepsloot South clinic who tested positive earlier this week after doing many community screening visits."
Without prompt results, he cautioned, the province risked losing the opportunity to move swiftly to contain local outbreaks.
Bloom said testing backlogs might mean Gauteng's Covid-19 figures were being underestimated.
The NHLS had processed about 92 000 Covid-19 tests in Gauteng as of 6 May - accounting for a third of all tests done by the national lab service nationally, according to figures released by the Gauteng health department.
The province leads the country in NHLS testing followed by the Western Cape and KwaZulu-Natal, which have logged about 54 000 tests each.
Currently, public labs perform about one in every two Covid-19 tests in South Africa and the NHLS recently added six more laboratories to those able to run the diagnostics.
Bhekisisa asked the national health department what delays in testing might mean for the country's national figures and high-level decision making. It had not responded at the time of publication. Bhekisisa will update this story as soon as it responds.
Patients are returning to work only to find out later they have the virus
Meanwhile, healthcare workers said they worry delays in results were putting people at risk unnecessarily. If patients had access to test results quickly, they could take measures to protect those around them - especially the loved ones they live with who are at a high risk of contracting the virus.
It also makes bad news even harder to deliver.
Nandi Msingizane, not her real name, is a public sector doctor in the Western Cape and spoke on condition of anonymity.
On Monday, she phoned three patients to deliver positive Covid-19 results for tests they had taken nine days earlier.
The next day, she picked up the phone again - this time to tell four patients they had also tested positive for the virus. The group had waited more than a week for their results.
"A full 10 days later," she tells Bhekisisa. "I'm almost too embarrassed to contact them. It makes a complete mockery of our community screening and testing policy."
Patients' reactions, she said, vary from downright anger to shock and fear for their families.
"I have many patients who returned to work or their families because they hadn't been contacted after two days, so they assumed their results were negative, only for their positive results to come out after seven days.
"One guy was furious that it had taken so long. He's a taxi driver and had gone back to work," Msingizane added.
"We are doing more and more tests every day. We're being told to expect to wait longer in the future. This is not feasible, especially with our increased community screening and testing."