Protecting the quality of HIV testing in the new HIV testing environment

20th International AIDS Conference | 24 July 20141 |

Protecting the quality of HIV testing in the new HIV testing

environment20th International AIDS Conference

24 July 2014, Melbourne

Anita SandsPrequalification Team – Diagnostics

Department of Essential Medicines & Health Products


Background

Quality of all HIV testing is a priority– Incorrect HIV testing results will occur without a framework to

guide quality of testing

3 C's to the 5 C's– Consent– Confidentiality– Counselling– Correct test results– Connection/linkage to prevention, care and treatment


Where to deliver HIV testing

Universal access to HTC

Community based HTC

Home-based

Quality standards for all HTC settings

Facility based HTC

Outreach (key pop)

Events

Workplace

Schools

PITCClinical settings

Other facilities e.g. stand-alone VCT


Framework for quality of HIV testing

Selection of testing strategy

List of prequalified diagnostics

National testing and QA policies

Validation of testing algorithm(s)

Procurement of diagnostics

Post-market surveillance

National regulatory framework for diagnostics

Training Quality assuranceSupported by

Guided by

Guided by


WHO Prequalification of Diagnostics

Pre-submission form

Dossier review Site inspection Laboratory evaluation

Dossier incomplete

Prequalification decision

Dossier complete

Dossier screening

Priority product

YesNo











Guided by

Guided by


Testing strategy for diagnosis: high prevalence >5%

Result: A1-Report: HIV

negative

Result: A1- A2-Report: HIV

negative

Result: A1+ A2-

Result: A1+ A2- A3+

Report: HIV inconclusive

Result: A1+ A2- A3-Report: HIV negative

Conduct A2

Result: A1+ A2+Report: HIV positive

Conduct A1

Result: A1+

Conduct A3

Result: A1+ A2-

Repeat A1 and A2

Source: HIV Assays Report 17 http://apps.who.int/iris/bitstream/10665/93679/1/9789241506472_eng.pdf


Testing strategy for diagnosis: low prevalence <5%

Result: A1-Report: HIV

negative

Result: A1+ A2 -Report: HIV

negative

Result: A1- A2 -Report: HIV

negativeResult: A1+ A2 +

Result: A1+

Result: A1+ A2 -

Repeat A1 and A2

Result: A1+ A2+ A3+

Report: HIV positive

Result: A1+ A2+ A3-

Report: HIV inconclusive

Conduct A2

Conduct A3

Conduct A1

Source: HIV Assays Report 17 http://apps.who.int/iris/bitstream/10665/93679/1/9789241506472_eng.pdf











Guided by

Guided by


Validation of testing algorithms

How to chose the assays to be used as Assay 1, Assay 2, and Assay 3?

Assay 1 = most sensitive– Assay 2 and Assay 3 = most specific– Poor choice of Assay 2 and 3 may lead to

high rates of misclassification

Defined national testing algorithms– With back-up options in case of stock-outs

or product failures


(Un) clear test instructions

Example of HIV diagnostic rapid test procedure:

1. Using one of the disposable pipettes supplied, fill with specimen.

2. Holding the pipette over the specimen well, add two drops of specimen (approx. 50μl).

3. Add 2 drops of buffer (approx. 60μl) to specimen well.

4. Allow 5 – 20 minutes from the time of buffer addition for the reaction to occur. For strongly positive results, the test line may become visible earlier. It is advisable to wait the full 20 minutes for negative results.


Critical parts of test procedure Volume of specimen

– Too little = reduced sensitivity

Volume of buffer– Too much = test may overflow– Too little = specimen will not flow

through the device

Reading time– Too soon = high background – Too late = reduced specificity


WHO post-market surveillance

WHO is developing guidance for both reactive and proactive elements of post-market activities

End-users, manufacturers, NRAs all have a role

WHO prequalified product

Reactive PMS

Field Safety Notice

Complaints Lot verification testing

Proactive PMS

Field Safety Corrective Action











Guided by

Guided by


Quality assurance

Using ISO 15189 as the standard and CLSI GP26-A4 as guidance

External quality assessment (EQA)

– Verifies the proficiency of the testing process

Quality Control (QC)– Verifies the test is working

correctly

Process Control Quality Control & Specimen Management

Purchasing & Inventory

AssessmentOccurrence Management

Information Management

Process Improvement

Customer Service

Facilities & Safety

Organization Personnel Equipment

Documents & Records


Assuring quality of community-based HTC Keep the service delivery model simple

Community workers (operators) must be trained and proficient in specimen collection, test procedure, reading of results, and interpreting results

Support from the laboratory is crucial

Ensure linkage to treatment and care – For additional testing to confirm the diagnosis, and preferably at

a site that performs treatment assessment i.e. CD4 count for ART initiation











Guided by

Guided by


Training and proficiency

Competency-based training

Proof of proficiency with panel of HIV + and HIV - specimens

– Proficiency for the entire testing algorithm, not just test procedure

Simple SOPs – Easy to read job aids


WHO normative guidanceWHO service delivery

approaches to HTC: a strategic policy framework

– http://apps.who.int/iris/bitstream/10665/75206/1/9789241593877_eng.pdf

WHO handbook for improving HIV testing and counselling services

– http://www.who.int/hiv/pub/vct/9789241500463/en/index.html


WHO/CDC training package

Training package– Participants manual – Trainers guides– Visual aids

Requires local adaptation

http://www.who.int/diagnostics_laboratory/documents/guidance/hivrttraining_overview/en/index.html

Undergoing revision