Spectrum Health Medical Staff Richard A. Horvitz MD, Clinical Pathologist June 23, 2014 New HIV confirmatory algorithm
Effective June 23, 2014 the Spectrum Health Laboratory will implement a new reflex testing algorithm for the confirmation of positive HIV (Human Immunodeficiency Virus) 1/2 EIA (Screening and Diagnostic) and HIV Quick Test results. The new reflex testing algorithm is consistent with current CDC guidelines for HIV confirmatory testing (references available upon request to Laboratory). Specimens with positive EIA results will now be further evaluated with a HIV-1/HIV-2 discriminatory test (Bio-Rad Multispot). EIA positive specimens will no longer be sent out to Mayo Medical Laboratories for the HIV Western blot test. The Multispot test will be performed in house, with results reported within 1 - 3 days after the positive EIA is encountered. This will provide substantially faster turnaround than waiting for the Western blot results to come back from Mayo. Specimens with positive HIV-1 results on the discriminatory test are considered confirmed positive for HIV-1 infection. It is recommended that a quantitative HIV-1 RNA (viral load) assay be ordered as a baseline for HIV-1 antiviral therapy. Specimens with positive EIA but negative or indeterminate results on the discriminatory test may indicate early HIV infection prior to positive results on the confirmatory test. It is strongly recommended that the quantitative HIV-1 RNA (viral load) assay be ordered on such patients. Patients with early HIV infection, with EIA results not yet confirmable as positive, typically have very high levels of HIV RNA. Again, this HIV RNA level should be used as a baseline for HIV-1 antiviral therapy. Comments indicating the above interpretive information and appropriate follow-up testing will be reported with the HIV-1/HIV-2 discriminatory test results. Similar comments will be reported with the other possible results (Undifferentiated, HIV-2 Positive) for the Multispot test. It is expected that these results will occur only rarely. HIV-2 is very rarely, if ever, encountered in the United States. Contact the Laboratory at (616) 774-7721 for further information on specimen collection for the recommended follow-up tests. A separate physician order is required for the HIV-1 RNA (viral load) assay (SH #4187, Epic #LAB2111092). This test requires a different specimen type than the EIA and discriminatory tests, and cannot be performed on the same specimen used for these tests. The HIV-1 RNA test will require a new patient draw for the needed specimen. New physician orders are also required for the other follow-up tests where indicated. Any questions concerning the HIV confirmatory testing algorithm may be directed to Dr. Richard Horvitz in the Pathology Department at (616) 267-2785 or by E-mail to
[email protected].
