The purpose of this study is to compare the results for HIV and/or Hepatitis C Virus antibody testing when using routine plasma versus SMARTplasma from the same blood sample. SMARTplasma is enriched for antibodies via a stimulation step of whole blood in a SMARTube™ (SMARTstim™ in the USA).

Following exposure to HIV and HCV, there is a "window period" where a person is infected with the virus but does not produce antibodies at a high enough level so they can be detected by antibody detection test methods. During this time, the person is capable of unknowingly transmitting the virus to others. SMARTstim (SMARTube)is a blood sample additive which pre-treats blood, stimulating antibody production in vitro so as to bring it to detectable levels using ELISA (or any other antibody test method). Accelerated antibody production allows antibody detection in specimens that would otherwise be below the detectable limit of antibody test kits. Plasma samples from blood pretreated with SMARTstim are referred to as "SMARTplasma".

A total of 1,600 blood samples will be collected and tested using an ELISA for HIV and HCV using FDA-approved test kits. The populations include:

• 1000 samples from low risk individuals (blood donors) from 3 geographical locations
• 500 samples from high risk individuals at risk for HIV from 2 geographical locations
• 100 known HIV seropositives

This is a non-linked study; that is, no subject identifiers will be associated with the collected blood. Subjects will not receive any correspondences and will not receive any test results.

If discordant results occur between the plasma and SMARTplasma samples, those samples will be retested. A Western Blot will be performed on ELISA repeat reactive discordant samples. HCV testing using an FDA-approved assay may also be performed using retained samples.

Simple statistical methods will be performed as necessary to analyze concordance of results between the sample types in the same ELISA assay.

Secondarily, it is expected that within the scope of this study, it will be shown that:

• Using SMARTplasma does not adversely affect diagnostic specificity of the HIV and/or HCV antibody assay used; i.e., no increase in the rate of HIV or HCV false positive results.
• Using SMARTplasma does not adversely affect diagnostic sensitivity of the HIV and/or HCV antibody assay used; i.e., no decrease in the number of true positive samples.
• Samples from persons with early or acute infection may show a positive result when using SMARTplasma, while those from plasma will test negative.
• SMARTplasma samples using heparin or EDTA collection tubes and the correlating SMARTstim are comparable.
• SMARTplasma samples that have been frozen show comparable results to correlating SMARTplasma samples that have been refrigerated.

Inclusion Criteria:

• Adults ages 18-64,
• Are not pregnant
• Not have a life-threatening disease
• Not immunosuppressed (HIV therapy allowed)
• Are able to give consent, and (6) who appear healthy.

Exclusion Criteria:

• Do not meet the inclusion criteria
• Are enrolled in an HIV vaccine study,
• Who have previously been enrolled in this study

Laboratory Sample from low risk population (i.e., blood donors), high risk population and known positive patients.