HIV test kits that may offer false negative results recalled

SINGAPORE — Individuals who did a rapid HIV test between last February and May this year have been advised to check with their clinics if they need to be rescreened, after a brand of test kit was recalled by the authorities.

These kits were found to have reduced sensitivity, potentially giving rise to false negative results in the early stages of infection. The Health Sciences Authority (HSA) said that 584 of the SD Bioline HIV Ag/Ab Combo kits were supplied to 27 healthcare facilities, including 26 clinics and one hospital. All have since been recalled.

Almost 13,700 tests, involving thousands of individuals, could have been conducted with the faulty kits.

The HSA spokesperson told TODAY that “547 (of the kits) have potentially been used, with each kit being able to perform 25 tests”.

She added that those who received negative results from the screening test using the affected lots, and are considered at high risk of HIV exposure, have already been advised by the clinics or hospital to return for one more test.

The advantage of the test kit is that it shortens the window period during the early stages of HIV infection, when blood tests may be unable to detect the infection — which is up to three months — enabling healthcare facilities to screen for it earlier.

In its press release yesterday, HSA said that it was notified by the Singapore importer, Unison Collaborative, that nine lots of the kit were recalled by the product owner, Standard Diagnostics Inc, due to their reduced sensitivity. “According to the manufacturer, when a patient is in the very early window period, the lower sensitivity of the affected lots may reduce detection, with the possibility of a false negative result for this subset of patients,” HSA said.

Eight patients had used the particular batch of test kit at Vienna Medical Clinic located in South Bridge Road, but all have since been reviewed, a doctor at the clinic said.

Dr Winston Lee, 35, said that “they have mostly been tested at one month (using the recalled kit) after risky exposure”. “In general, we have a practice of encouraging our patients to come back for frequent testing (every three to six months), and to practise safer sex through the use of condoms,” he added. “We are also contacting our patients actively to encourage them to return for a retest with the newly provided test kits.”

Sagemed, a clinic in Mount Elizabeth Hospital, said that it used the test kit on just one patient, and is still identifying the person. “We need to check our records … to find out which patient used the kit,” its representative said.

General practitioner Jeremy Chan, 32, who has his own private practice in Toa Payoh Lorong 1, said that he had promptly replaced the kits before they were used on any patient.

“I was informed by the supplier of this news shortly after I placed my order. I have since done an exchange of the test kits with the supplier.”

Three other clinics contacted by TODAY declined to reveal the number of patients who had used the kit, but said that they have reached out to the affected patients for a retest.

CORRECTION:

An earlier version of this story said those who had taken a rapid HIV test between February and May should check with their clinic to see if they need to be rescreened. The correct time frame should be from February 2016 to May 2017. We are sorry for the error.