Diagnostics
Comparison of Salivax™ HIV Saliva Test and Enzyme Immunoassay for Diagnosing the Presence of Antibodies to HIV-1 and HIV-2
Edmund P Kemprud,1 Shannon A Montano,2 Geeta S Kalbag,3 Alesia SO Tam,3 Victor I Martin4
1. Medical Director; 2. Chief Nurse, Amador Valley Medical Center, Dublin, CA; 3. Research Scientist; 4. Vice President; 5. President and Chief Executive Officer, ImmunoScience, Inc., Pleasanton, CA
and Sateesh N Apte5
Abstract
The current methods of detecting exposure to HIV types 1 and 2 involve a serum enzyme-linked immunosorbent assay (ELISA), Western immunoblotting and polymerase chain reaction (PCR). All of these techniques require collection of blood, trained personnel and sophisticated lab facilities. There is also an inherent danger in collection of blood samples, especially in environments where disposable needles are not commonly used. As a result, the prevalent methods are impractical for use in the field and for mass screening, particularly in the developing world and in epidemic situations. This study compared a saliva-based rapid immunoassay with conventional ELISA. A total of 1,192 paired samples of saliva and blood from six Northern California locations were obtained. The saliva samples were subjected to the Salivax™ HIV immunoassay and the blood/serum samples were tested with US Food and Drug Administration (FDA)-approved BioRad® enzyme immunoassay (EIA) in a College of American Pathologists (CAP)-certified laboratory. The comparison of results showed Salivax HIV to have a sensitivity of 99.53 % and a specificity of 99.74 %. This study confirms several prior studies that indicated that saliva is an extremely useful biological fluid for antibody screening and further indicates that Salivax HIV has the necessary sensitivity and specificity to act as a screening test, particularly in the highly populated, developing and rural world and as a point-of-care test.
Keywords HIV-1, HIV-2, diagnosis, saliva, oral fluid, Salivax, assay
Disclosure: Geeta S Kalbag, Alesia SO Tam and Victor I Martin are employees of ImmunoScience, Inc. Victor I Martin and Sateesh N Apte directly or indirectly own or control shares of ImmunoScience, Inc. Received: 29 July 2011 Accepted: 8 August 2011 Citation: European Infectious Disease, 2011;5(2):146–9 Correspondence: Edmund Kemprud, c/o Victor Martin, 6670 Owens Dr, Pleasanton, CA 94588, US. E:
edmundkemprud@gmail.com
Support: The publication of this article was funded by ImmunoScience, Inc.
Currently, the screening of serum by enzyme-linked immunosorbent assay (ELISA) and confirmation by Western blot is a common testing strategy, but the World Health Organization (WHO) has recently suggested that alternative testing algorithms that reduce the need for the Western blot can be used successfully to screen blood for transfusion safety, and for surveillance and diagnostic purposes.2 These alternative strategies are simpler and less expensive to perform and can provide more objective results.3
Serological testing using blood samples is the most widely used method for the diagnosis of HIV infection and has been employed routinely since 1985.1
Recently, the use of oral fluids such as saliva for detecting antibodies to HIV has been suggested as an alternative to the use of blood,4–7 based on the previous demonstration of specific immunoglobulin (Ig) in oral fluids. Both IgA and IgG are present in oral fluids with IgA being derived primarily from the salivary glands, while IgG reaches the oral cavity mostly through the transudation of serum components from the capillaries beneath the buccal mucosa;8
however, the levels of IgG
are much lower than those in serum, which has raised some concern about whether IgG can be adequately detected in oral fluids. Although the results of a number of studies suggest that the use of oral fluids may be appropriate for several testing situations, there remain a number
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of issues that must be addressed before their use can be recommended for HIV antibody testing.9
have also been detected in oral fluids. Furthermore, oral fluid samples have been used to detect the presence of a variety of substances including hormones, therapeutic drugs, cocaine, caffeine and tumour markers. Testing for antibodies to HIV using oral fluids was introduced in the mid-1980s;10,16–25
Oral fluid samples can be used successfully to detect antibodies to a variety of viral agents including hepatitis A virus, hepatitis B virus, rubella virus10–12 and HIV antigen15
and hepatitis C virus.13 Hepatitis B surface antigen14 since then, the performance of a
variety of HIV serological assays, using several types of oral fluids, has been reported. The results are encouraging, and several reports suggest that oral fluid samples can be used successfully as an alternative to serum samples for HIV testing. However, test performances vary depending on the tests used and the methods of collecting oral fluids.26,27 Several oral fluid collection devices have been developed and one assay has been designed specifically for testing these types of fluids.28
Currently, there is considerable interest in the use of oral fluids for HIV antibody testing and many individuals are seeking advice about the accuracy and advantages of such testing.9
This article describes some © TOUCH BRIEFINGS 2011
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