VCT laboratories that follow quality testing protocols

Export Indicator

Percent of HIV tests requested by voluntary counselling and testing centres over a one month period which follow recommended testing algorithms
What it measures

As countries work to expand access to quality voluntary counselling and testing procedures for HIV, great emphasis has been placed on the training of counsellors. In some countries, less attention has been paid to ensuring that the test results themselves properly reflect sero-status. This is of vital importance in the context of VCT, where people are informed of their HIV status. The consequences of wrongly informing people that they are HIV positive or HIV negative can be devastating, both for the individual and for their sexual partners. Because of this, the protocols recommended for HIV testing when a person is to be informed of their status are more rigorous than those used for surveillance or blood safety purposes. While sensitivity and specificity of HIV test kits have reached very high levels, no test is infallible, and this is especially true of tests affordable enough to be used in high-volume screening sites such as VCT centres. WHO has therefore developed protocols, adopted by many countries, to minimise the risk that someone will receive an incorrect HIV test result. These protocols set down algorithms for the re-testing of samples using different tests. A minimum of two tests are required before a person can be informed of their HIV status. Where the first two tests disagree, further different test types are used to confirm a result. This indicator tracks the extent to which these algorithms are followed by laboratories performing tests for VCT centres.

Rationale
Numerator

Number of HIV tests requested by voluntary counseling and testing centres over one-month period which follow recommended testing algorithms

Denominator

Total number of HIV tests requested by voluntary counseling and testing centres over a one months period

Calculation
Method of measurement

A retrospective record review is carried out at laboratories processing specimens taken at VCT centres.  The review looks at all samples processed over a defined one-month period prior to the review. It examines whether testing algorithms are being followed according to national or international recommendations (in other words, whether samples are being retested using different test kits to eliminate false positives and false negatives to the extent possible). The sample frame will depend on a country’s national programme. In some countries, large VCT centres have their own laboratory facilities, while in others specimens are processed at central, provincial or district laboratories. In countries with centralised or limited facilities, the review may be conducted at all relevant sites where specimens are tested for  VCT purposes. In countries with larger programmes, records from random samples of sites stratified by urban or rural location may be reviewed.

Measurement frequency

Periodic

Disaggregation

Education: N/A

Gender: N/A

Geographic location: N/A

Pregnancy status: N/A

Sector: N/A

Target: N/A

Time period: N/A

Type of orphan: N/A

Vulnerability status: N/A

Explanation of the numerator
Explanation of the denominator
Strengths and weaknesses

This indicator has the virtue of being relatively simple to construct. A major limitation is that it only addresses one dimension of laboratory quality. Any number of repeat tests will not improve the quality of the results available to clients of VCT centres if the laboratory procedures themselves are flawed. Poor cleaning of testing equipment or repeat use of simple equipment such as pipettes can compromise the quality of all tests performed, regardless of whether they are for surveillance, diagnosis or VCT. It is expected that all countries promoting VCT have national guidelines on basic laboratory quality control, such as the re-testing of a proportion of all samples at a reference laboratory

Further information