# Presentation: 285879

## Update on HIV Rapid Tests

**Update on ****HIV Rapid Tests**

- Carol Fridlund
- Bernard M Branson, MD
- Centers for Disease Control and Prevention

## CDC Efforts and the Availability of Rapid Tests

*Encourage manufacturers to commercialize rapid tests in the United States.*
*Conduct clinical trials to establish test performance in settings of intended use.*
*Evaluate use of specific combinations of rapid tests to increase predictive value.*
*“**Treatment IDE” for expanded access to rapid tests*

## Interpreting  Rapid Test Results

*For a laboratory test:*
***Sensitivity***:  Probability test=positive  if patient=positive
***Specificity***:  Probability test=negative if patient=negative

***Predictive value***:
- 		   Probability patient=positive  if test=positive
- 		   Probability patient=negative if test=negative

## Example:	Test 1,000 persons 

**HIV prevalence = 10%****	****	**

**True positive:**

**False positive:**

**Positive predictive value:**

**100/104 = ****96%**

**100**

**4**

**Test Specificity = 99.6%**

***(4/1000)****** ***

## Example:	Test 1,000 persons 

**	****	****Test Specificity = 99.6%  *****(4/1000)***

**HIV prevalence = 10%**
**True positive:  100****	****	****False positive:   4 **
**	****Positive predictive value:  100/104 = 96%**

**HIV prevalence = 0.4%**

**True positive:**

**4**

**False positive:**

**4**

**Positive predictive value:**

**4/8 = ****50%**

## Predictive Value: Single Screening Test

**Test Specificity 99.6%**

- _HIV Prevalence_            _Predictive Value Positive_

-   10%				96%

-     5%				91%

-     2%				80%

-     1%				67%

-  0.5%				50%

-  0.3%				38%

-  0.1%				18%

-    3%                                    86%

## Determine

**Determine**

- Add serum or whole blood & buffer

**Add 1 drop specimen to pad**

## Read test results in 15 minutes

**Negative          (Reactive control)**

**Positive**

## OraQuick:  Whole blood, serum, oral fluid

**OraQuick:  Whole blood, serum, oral fluid**

**Oral fluid specimens can reduce hazards, facilitate testing in field settings**

**OraQuick**

## Add 5 μl specimen to vial;  insert paddle

**Add 5 ****μl specimen to vial;  insert paddle**

## Positive

**Positive**

**Negative**

**Reactive Control**

**Positive HIV-1/2**

**Read results in 20 minutes **

## Multispot HIV-1/HIV-2

**Multispot HIV-1/HIV-2**

## Dilution of plasma or serum

**Dilution of plasma or serum**

## Several reagent & wash steps

**Several reagent & wash steps**

## Negative

**Negative**

**HIV-1 & HIV-2 Positive**

**Peptide HIV-2**

**Recombinant HIV-1**

**Peptide HIV-1**

**Reactive Control**

## Rapid Test Performance: Plasma

***341 HIV+, 466 HIV- persons***

## Rapid Test Performance: Prospective Study

***1214 Clients at Testing Site /STD Clinic***

## Treatment IDE

*“**Investigational Device Exemption” from FDA*
*Allows use of investigational tests in certain populations and situations*
*Requires investigator, protocol, IRB approval*
*Manufacturer:  single test*
*CDC: plans several tests in combination*

## Next Steps

- Evaluate combinations of rapid tests for screening and diagnosis
- Determine eligibility for CLIA waiver
- Repeat evaluations with new crop of tests