Availability of Abbott / Murex Single Use Diagnostic System (SUDS) HIV-1 Test

In a letter dated October 18, 2000, Abbott Diagnostics informed their customers that the Abbott / Murex Single Use Diagnostic System (SUDS) HIV-1 test, the only rapid HIV test currently licensed for the U.S. market, will not be available for an undetermined period of time due to manufacturing problems. FDA has received assurance from Abbott that the company is working to resolve these problems as quickly as possible.

The most significant impact that the shortage of this test has is in healthcare situations where transmission of HIV may be prevented if therapy is initiated within 24 to 48 hours. These situations include testing of the source patient in the event of healthcare worker needlestick injuries and testing pregnant women presenting for delivery with an unknown HIV status. In both cases, initiation of treatment as soon as possible after the event (optimally within a few hours rather than days for needlestick exposures or within 12-24 hours after delivery for the newborn) is recommended by CDC and may decrease the number of transmissions when instituted within that timeframe. In these situations, many healthcare providers have been using the SUDS test to provide an initial result in 10 minutes.

While there are no other approved rapid HIV tests for use during this time, there are several possible interim measures which may be undertaken by healthcare providers. These include:

Immediate testing with one of the currently licensed enzyme-linked immunoassays (EIAs). These tests can usually be performed in 90 to 160 minutes (list of licensed tests). Typically, samples are tested in batches so that results may not be available for several days. However, if healthcare providers arrange for the EIA tests to be performed on samples as needed, results could be available within 90 to 160 minutes. In order to validate whether a reactive result is repeatedly reactive, any sample testing reactive on the initial assay (EIA or SUDS) normally would have to be repeated in duplicate in a separate assay. To avoid a lengthy delay due to a second round of testing of any initially reactive samples, performance of the initial assay in triplicate should be done. Repeatedly reactive samples would be those found reactive in at least two of the three replicate tests.

Use of the Sano Chemia (originally Waldheim) Fluorognost HIV-1 Indirect Immunofluorescence Assay (IFA), which is licensed as a screening test where EIAs are not practical. This test requires a fluorescence microscope and a well-trained technician and can be performed within about 100 minutes. No further testing is necessary for either negative or positive test results.

Although urgent medical decisions can be based on the result of a screening test for HIV, repeatedly reactive screening test results should be confirmed by the performance of a supplemental test. Approved supplemental tests for HIV include the indirect immunofluorescence test (IFA) test or western blot tests. The IFA test takes about 100 minutes to perform, while a western blot can be done in as little as 150 minutes (more typically western blots include an initial overnight incubation). In any case, the minimum time for providing a confirmed positive result would be 190 minutes with an EIA test (initial run in triplicate) as compared to 120 minutes with the SUDS test.

Since the length of time that this test will not be available is not certain at this time, FDA recommends that healthcare providers implement one of the suggested interim measures to replace the SUDS HIV-1 Test while it remains unavailable. The long range solution to this problem will include the availability of multiple rapid HIV tests. FDA continues to encourage the development of rapid HIV tests and has recently taken action to facilitate approval of rapid HIV tests as evidenced by presentations made during Blood Products Advisory Committee Meetings that have taken place this year (see transcripts of June 15 and September 15, 2000 BPAC).

Healthcare providers with questions, concerns, or suggestions should contact the Center for Biologics Evaluation and Research's (CBER) Consumer Affairs Branch, Office of Communication, Training and Manufacturer Assistance at 800-835-4709 or 301-827-1800.

Murex SUDS HIV-1 (Rapid EIA) - MedWatch - 10/18/2000