Beware Rapid HIV Testing in Late-Stage AIDS

Abigail Zuger, MD


AIDS Clinical Care 

Impaired antibody response in an AIDS patient compromised the accuracy of the test.

The OraQuick Advance Rapid HIV-1 Antibody Test has transformed HIV testing from a cumbersome process to a rapid while-you-wait affair. Unfortunately, the price of speed is accuracy: Recent reports have described false-negative results in early HIV infection (AIDS Clin Care Aug 20 2007) and a spate of false-positive results when the test is performed on oral secretions (AIDS Clin Care Jul 7 2008). A new case report now highlights the test's fallibility in late-stage AIDS.

A 28-year-old man came to a Michigan emergency room repeatedly during a 9-month period. Oral candidiasis was documented on three occasions. On two such occasions, the OraQuick HIV test was performed on oral swab samples; both were negative. Ultimately, the patient was hospitalized with confirmed Pneumocystis jirovecii pneumonia. OraQuick testing was again negative, but standard ELISA and Western blot tests confirmed HIV infection. The patient had a CD4 count of 4 cells/mm3 and a viral load >100,000 copies/mL; examination of his Western blot results showed a strong gp160 band, but other bands, including gp41, were very weak.

Because the OraQuick test contains only a single glycoprotein antigen (anti-gp41), it will not identify HIV-infected individuals who fail to mount a substantial response to that particular antigen. These individuals may include the newly infected as well as persons with such late-stage infection that their antibody responses to HIV have been compromised by the infection itself. The bottom line: When clinical signs point to HIV infection, do not be deterred by a negative rapid test. Assume that this testing may be fallible and proceed to the gold-standard ELISA and Western blot tests as well as measurement of viral load.

— Abigail Zuger, MD

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