1. HIV Testing Quality Assurance and Quality Control
Eligius Lyamuya MD, MMed, PhD
Department of Microbiology and Immunology
Muhimbili University of Health and Allied Sciences

2. Disposition HIV Diagnosis HIV Testing techniques Quality Issues Tests
Strategies
Algorithms
Quality Issues
Quality management QC QA
Quality improvement
Quality system

3. HIV Diagnosis

4. Requirements for Laboratory diagnosis of HIV infection
Standard Laboratory facility
Suitable physical structure
Well equipped with essential facilities
Human resources
Well trained
Adequate number
Test kits
Acceptable quality
Constant supply
Financial resources
Quality management

5. Diagnosis of HIV/AIDS Clinical criteria Laboratory Techniques
WHO and CDC criteria
Laboratory Techniques
Isolation of the virus in culture
Detection of viral antigens e.g. p24 ag
Detection of viral nucleic acid by polymerase chain reaction (PCR)
Detection of specific antibody to HIV antigens

6. HIV Testing Techniques

7. HIV testing Campaign in Tanzania
20/04/2017 7

8. Nucleic acid detection by Polymerase Chain Reaction (PCR)
HIV Testing
Antibody tests
Enzyme-Linked Immunosorbent Assays (EIA)
Western Blot
Rapid tests
Antigen tests
EIA P24 tests
Nucleic acid detection by Polymerase Chain Reaction (PCR)

9. Time from Infection to Detection of HIV-1 Markers
KEY:
NO DETECTION
EARLIEST POSSIBLE DETECTION OF HIV
Antibody assays
p24
DNA PCR
RNA PCR 5 10 15 20 25 30 35
Detection of HIV: Days after infection

10. HIV diagnosis in Adults and Children >18 months
Antibody-based tests (detection)
Most commonly used assays:
ELISA
Rapid Tests
Western Blot

11. HIV Diagnosis in Children <18 months
Antibody detection cannot be used due to presence of maternal antibodies
p24 antigen detection test is used
HIV nucleic acid (DNA or RNA) detection by PCR

12. HIV Testing - ELISA Quantitative assay to measure HIV antibodies
Some assays can detect both HIV antibody and HIV antigen (reduce window period)
Issues:
Skilled lab technician
Availability of reader, washer, incubator
Properly maintained equipment required
Power
Ideal for large volume testing
STATE points on the slide

13. HIV Testing – Rapid Tests
Qualitative assays to detect HIV antibodies
Most detect both HIV 1 and HIV 2
As reliable as ELISA
Provide same-day results
Do not require additional equipment
Issues:
Small volumes
Validation of use
Appropriate training
Added advantage for HIV rapid tests is the ability to use whole blood

14. Testing Strategies
Testing approach used to meet a specific need, such as:
Blood Safety
Surveillance
Diagnosis

15. WHO HIV Testing Strategies: Criteria
Criteria for choosing HIV testing strategy
Test objective: surveillance, blood screening, diagnosis
Sensitivity and specificity of the test(s)
HIV prevalence in the population
NB:
The HIV test strategy must be validated for use
by each country

16. WHO HIV Testing Strategies-1
Strategy I
Requires one test
For diagnosis where prevalence among persons with clinical signs is >30%
For surveillance where HIV prevalence is >10%

17. WHO HIV Testing Strategies-2
Strategy II
Requires up to two tests
For diagnosis where prevalence among persons with clinical signs is 30% or >10% among asymptomatic persons
For surveillance where HIV prevalence is 10%

18. WHO HIV Testing Strategies-3
Strategy III
Requires up to three tests
For diagnosis where prevalence among asymptomatic is 10%

19. HIV Testing Strategies
Serial testing
Samples tested by a first test
Result of first test determines whether additional testing is required
Parallel testing
Samples are tested simultaneously by two different tests

20. Testing Algorithm
The combination and sequence of specific tests used in a given strategy
An HIV Positive status is based upon the outcome of 2 or more tests
When two test results disagree (one is reactive, the other non-reactive), the finding is called “indeterminate.” In this case, a third test (tie- breaker) must be performed
The order of the tests in the algorithm is important.

21. HIV testing algorithms
EIA screen followed by Western blot confirmation
Multiple EIAs screen and confirmation
Multiple rapid tests screen and confirmation
UNAIDS, WHO and CDC have recommended and set guidelines for the use of HIV tests in screening and confirmatory algorithms

22. Current National HIV Rapid Testing Algorithm
Blood Sample
Bioline
Non-reactive Result
Report: Negative
Reactive Result
Determine
Reactive Result
Report: Positive
Non-reactive
Result
Unigold
Reactive Result
Report: Positive
Non-reactive Result
Report: Negative

23. Quality Issues

24. Laboratory quality management
All activities of the overall management function that determine quality policy objectives and implement them within a system
Components:
quality control
quality assurance
quality improvement

25. Quality Control-1
Operational techniques and activities used fulfill requirements for quality
Internal QC: set of procedures for continuously assessing laboratory work and emergent results
running “QC” samples
reading the “control” line
evaluating signal to cutoff ratios for QC samples
having another technologist review test interpretations, calculations, etc

26. Quality Control-2
External QC: of evaluating the performance of a laboratory in testing samples sent by an external laboratory
running proficiency testing samples
retesting a proportion of samples

27. Quality Assurance
A dynamic and ongoing process of monitoring a system for reliability and reproducibility of results that permits corrective action when established criteria are not met
Takes into consideration pre-analytical, analytical and post-analytical phases

28. The Quality Assurance Cycle
Data and Lab
Management
Safety
Customer
Service
Patient/Client Prep
Sample Collection
Sample Receipt and Accessioning
Record Keeping
Reporting
Personnel Competency
Test Evaluations
Testing
Sample Transport

29. QA: Pre-analytic Select the best test and testing strategy
which test
what algorithm
which laboratories
Assess testing services before starting testing
Designate responsibilities and make clear the decision making process
Make sure each testing site has reagents and supplies
Have standard operating procedures in place (SOPs)

30. QA: Analytic
Provide every testing site with instructions and training for:
laboratory safety
sample receipt (sample assessment and rejection criteria, logging-in process and forms)
sample storing
how to do testing
how to perform internal QC and external QA and/or proficiency testing
how to monitor other testing parameters (e.g., strength of signal for a QC sample)
Perform competency checks of laboratory personnel who manage samples and do testing
on-site audits
competency evaluation panels
review recent proficiency testing data

31. QA: Post-testing
Set up a process for evaluating test results and QC indicators before releasing test results
Establish corrective actions to take when indicators are of control indicators
Establish a review process to assure accurate results transcription and reporting
Store samples properly for retesting and/or referral

32. Quality Improvement
Determination of causes or sources of problems identified by QC and QA

33. Quality System
Organizational structure, resources, processes and procedures needed to implement quality management

34. Quality System Essentials
Organization
Personnel
Equipment
Purchasing and inventory
Process control
Information management
Documents and Records
Occurrence management
Internal assessment
Process improvement
Service and satisfaction
Facilities and safety

35. Quality System
Quality Assurance
Quality Control

36. Take Home Messages
Not paying attention to QA is like starting a journey without knowing how to drive, without doing routine maintenance and without adding fuel
If QA and QC is done correctly, troubleshooting will be a rare event and easy to do
Laboratories without QC never make mistakes, because they never detect them
Even simple tests, require some QA
The fewer the steps in a process the simpler the QA.

37. THANK YOU