HIV Test Of Blood, Urine More Accurate
October 31, 1997
NEW YORK (Reuters) - HIV tests could be more accurate if they looked for antibodies in both blood and urine, suggests a clinical trial by a manufacturer of a urine-based HIV test.
In some rare cases an individual may have a negative blood test for HIV antibodies while a urine test reveals that they are indeed infected with the virus that causes AIDS, according to a report in the journal Nature Medicine.
"This study demonstrates that neither serum nor urine results alone are as sensitive for HIV-1 antibody detection as combined results of both samples," wrote lead author Dr. Howard Umovitz, chief science officer at the Calypte Biomedical Corporation in Berkeley, California.
In a study of 11,344 people, 1,181 people were HIV positive. In a small number of cases (10), individuals had a negative blood antibody test and a positive urine test. The opposite occurred in 15 patients who had a negative urine test but positive blood test. Therefore, the blood tests detected 99.15% of HIV-positive individuals and the urine tests detected 98.73%. If both tests were used, it would have detected 100% of people who were later confirmed to have HIV by the highly sensitive Western Blot test, according to the report.
In some cases, HIV may "compartmentalize," infecting only certain organs or tissues or prompting an antibody response in only certain parts of the body, according to the researchers from Calypte, who conducted the study in an effort to get licensing for the urine test.
"The results of this large clinical study support this concept," they wrote. "Public health policies may need to be revised in settings where absolute sensitivity for HIV-1 antibody testing reflect life-or-death decisions. Combination sampling with at least two body fluids may assist in the process of such decision-making."
SOURCE: Nature Medicine (1997;3:1258) |
