# Presentation: 706032

## HIV Testing of Dried Blood Spots:An Evaluation of HIV Kits in Botswana 

- Rachanee Cheingsong, PhD (CDC)
- Sarah Gaolekwe, BSc, MSc,
- Wilson Kalake, OND MLT (NBTC)
- Presented by:
-  Kyle Bond, M.S. (CDC)

## Acknowledgements 

- T Bokete (MOH)
- K Masupu (NACA)
- L Manthe (MOH)
- C Mwangi (NRHL)
- NBTC, BOTUSA, Harvard staff
- T Kenyon (BOTUSA)
- H Jaffe, M Rayfield, K Bond, T Grenade, J Mei, Li Xia (CDC)

## Dried Blood Spots

- An easy way to collect and transport blood specimens for investigational purposes
- Blood collected and dried on FDA-approved blood collection device
- 100 ul/spot
- Plasma + cells
- Source of antibody, DNA, RNA

## Applications of Testing Dried Blood Spots 

- Newborn babies screening program in the US
- 	Over 30 inherited and metabolic disorders
- 	Maternal HIV antibodies
- Potential applications:
- 1.   HIV surveillance and VCT program
- 2.   Newborn babies screening (PMCT)
- 		- HIV infection
- 3.   HIV Drug Resistance

## HIV Surveillance and VCT Program  

- 1.   On-site HIV rapid testing
- 2.   _**Dried blood spots (DBS) collection for HIV testing at reference labs**_

## HIV Testing of DBS in VCT setting

- Quality control purposes
- Performance of rapid tests and personnel
- Self monitoring and evaluating of the program

## HIV Testing of DBS: A Pilot Study in Atlanta 

- DBS seroconversion panels (A-E)
- Ugandan DBS panel (n=186)
- Mock DBS
- 7 HIV EIA kits (FDA and non-FDA approved)
- 5 Were not validated for DBS
- The accuracy of the kits was high >97%.

## Objective 

- To determine the accuracy of HIV EIA testing on DBS
- To evaluate the performance of HIV kits for testing DBS in a laboratory setting in Botswana.

## Action Plans

- July 23rd -Aug. 17th 2001: Pilot Activities
- Discussion, planning
- Protocol preparation
- Generating a panel of DBS
- Storage and record of specimens
- HIV Testing
- Data entry/analysis
- Comparison of DBS data against serum results
- Summary

## Collection of EDTA blood at National Blood Transfusion Center, Gaborone 

| Week | Blood Donors | Surveillance |
| --- | --- | --- |
| 1 | 227 | 0 |
| 2 | 46 | 88 |
| 3 | 38 | 35 |
| Total | 311 | 123 |

## HIV Testing in Botswana

- Serum/plasma: 	1. Murex 1.2.0
- 			       	2. Ortho
- DBS :		1. Murex 1.2.0
- 				2. Ortho
- 				3. Murex GacElisa 					    (validated)

## HIV Status 

| Source | HIV +ve/Tested | % prevalence |
| --- | --- | --- |
| Blood Donors | 11/311 | 3.5 |
| Sentinel Surveillance | 51/123 | 41.5 |

## Flow Chart of DBS Testing

- Murex GacElisa *

- Murex 1.2.0

- Ortho

**Flow Chart of DBS Testing**

- Elution with PBS

## Mean Absorbance of HIV-ve DBS (n=300) increased 

- HIV kits			Mean OD Units
- 				Serum		DBS
- Murex 1.2.0	0.106		0.135
- Ortho		0.010		0.047
- GacElisa		N/A			0.070

## HIV Testing of DBS by GacElisa

| Serum HIV | DBS +ve | DBS -ve |
| --- | --- | --- |
| HIV +ve       n=62 | 61 | 1 |
| HIV –ve       n=372 | 1 | 371 |

## HIV testing of DBS by Murex 1.2.0

| Serum HIV | DBS +ve | DBS -ve |
| --- | --- | --- |
| HIV +ve       n=62 | 61 | 1 |
| HIV –ve       n=372 | 4 | 368 |

## HIV testing of DBS by Ortho

| Serum HIV | DBS +ve | DBS -ve |
| --- | --- | --- |
| HIV +ve       n=62 | 61 | 1 |
| HIV –ve       n=372 | 0 | 372 |

## Performance of HIV kits on DBS

| HIV Kits | Sensitivity (%) | Specificity (%) |
| --- | --- | --- |
| Murex 1.2.0 | 98.3 | 98.9 |
| Ortho | 98.3 | 100 |
|  GacElisa* | 98.3 | 99.7 |

## Summary

- Results of DBS were reasonably comparable to serum results with an exception of one weakly +ve sample.
- The three kits evaluated with DBS gave comparable results (98% sensitivity, 98-100%  specificity).
- Among three kits evaluated, only GacElisa is validated for DBS.

## Plan for weakly +ve samples

- Start collecting this type of samples
- Generating a panel
- Evaluating HIV kits
- Increase sensitivity of HIV kits
- Feed back to manufacturers

## Selection of HIV kit(s) for DBS 

-        _**GacElisa vs Ortho vs Murex 1.2.0 ?**_
- -- Assay validation
- Practical issues
- Dilution factors (Murex and Ortho)
- 1 or 2 assays ?
- Evaluating more HIV kits that use the same format as GacElisa ?

## Proposal for Future Activities 

- Prospective collection of DBS at VCT sites
- Large sample size
- Evaluation of selected kits with DBS
- Compare results with rapid tests
- Generating a QC panel
- Testing algorithm for DBS