The price of quicker HIV test results

01 Dec 2006, Today

Question

The price of quicker HIV test results

Why 2-week wait for HIV test results? 

With cases on the rise, outdated practice should be scrapped Wednesday - November 29, 2006 Letter from Lim Boon Hee 

I APPLAUD the initiative by the Government to set up a high-level committee to tackle the increasing number of cases of HIV in Singapore ("New command in Aids battle", Nov 28). 

Apparently the number of new HIV cases has escalated from from 0.8 per million to 89.2 per million in 21 years - an enormous increase. 

I hope the committee led by Dr Balaji Sadasivan will look urgently into the anomaly that, despite the multiplying number of HIV infections, it still takes two weeks to confirm any case of HIV in Singapore. 

All laboratories here must send any abnormal HIV blood samples to the Singapore General Hospital's National HIV reference Laboratory for confirmation via the Western Blot test. 

More than a decade ago, when there were much fewer HIV cases, it made sense for the the hospital lab to pool all abnormal blood samples sent to them and test them in batches just once or twice a week. 

But apparently, despite the greatly-changed HIV situation now, the sole laboratory authorised to do a Western Blot Test is still sticking to this archaic practice. Clinics are specifically told not to chase the lab to expedite HIV results. The anxiety of waiting a fortnight for HIV test results can be extremely agonising for patients or foreign workers. 

Times have changed, and I urge the high-level anti-Aids committee to look into expediting HIV confirmation if it is to tackle this serious problem effectively. 

As it is, doctors' hands are tied in the fight against HIV - oly through Singapore's single equipped laboratory can they give their patients confirmation, and only after two weeks. If it takes this long, we will have lost the Aids battle even before we start.

Reply

Name of the Person: Ms Karen Tan

Director, Corporate Communications

Ministry of Health 

The price of quicker HIV test results 

In "Why 2-week wait for HIV test results?" (TDY, 29 November 2006), Mr Lim commented that the new National HIV/AIDS Policy Committee should look into shortening the turn-around time for the Western Blot confirmatory HIV tests. We understand the anxiety of patients and will do our best to shorten the waiting period without compromising accuracy of the test result or increasing the cost to the patient. 

For HIV screening, the tests are done daily. Screening tests which are negative do not require further confirmatory testing and the results are available to persons being tested within two or three days. Only positive screening test results require confirmatory testing. There are several factors to consider in deciding whether the frequency of confirmatory testing should be increased. 

First, the vast majority of HIV screening tests in Singapore have negative results. Last year, out of a total of about 720,000 such tests performed, only about 2,600 tests had positive results (0.4%). This means that for every 1,000 tests, 996 are negative.

Second, only about 500 of the 2,600 positive tests in 2005 came from Singaporeans. The bulk of HIV screening tests are carried out as part of medical screening for statutory or employment purposes. 

Third, the National HIV Reference Laboratory at the Singapore General Hospital (SGH) receives between 30 and 50 samples a week for confirmatory HIV testing. It has to exercise extreme care to ensure the absolute accuracy of the final test result. The gold standard for confirmatory HIV testing uses the Western Blot and this requires specialised expertise and good experience. To maintain cost-efficiency, SGH conducts up to two Western Blot runs a week to process these samples. Nearly all of these confirmatory results are made known to doctors within 9 days. Some results are made known in less than a week depending on which part of the week the samples are dispatched to the Laboratory. In rare instances, results may take up to 14 days to be available if the confirmatory tests have to be repeated. 

Fourth, the volume of confirmatory testing in Singapore (30 to 50 samples a week) does not justify the setting up of a second HIV reference laboratory. The frequency of confirmatory test runs can be increased so that results are available within a week. However, this will double the costs of the confirmatory testing programme, which is currently about $250,000 a year. This would not be cost-effective in view of the relatively small number of persons involved. 

Finally, doctors play an important role in managing the patient's anxiety when they come for HIV testing. Patients need to be counselled so that they are aware of the significance of HIV testing and doctors should help their patients manage their fears. 

The prevention and control of the HIV epidemic in Singapore requires a multi-faceted approach. The National HIV/AIDS Policy Committee will continue to engage the community to fight against this disease.