Laboratory services are a critical and core component of the NACP. Increasingly, it is being recognised that work related to laboratory services is not confined to HIV testing alone, but is overarching and impacts on other NACP interventions such as prevention, care, support and treatment, STI management, safety of blood and blood products, procurement and supply chain management. Emphasis on quality assured laboratory service delivery is paramount to the success of NACP.
Laboratory diagnosis is the only method of defining/establishing HIV status of an individual. India has well developed laboratory approaches for: ensuring blood safety and donation (tissue, organs) safety; surveillance of high risk groups; sentinel surveillance; diagnosis and research.
Most of HIV antibody screening and supplemental (some Labs. only) testing is performed at the local level (ICTCs, PPTCTCs, Surveillance Centres under NACO), while centralised (referral) labs. provide reference diagnostic services for problematic sera and perform sophisticated technique like W.B., PCR and viral load assay, etc. There is a vast network of HIV testing laboratories in India and a wide variety of test kits are used by them to produce reliable, accurate and reproducible results.
Regardless of the level of the laboratory involved in HIV testing, the training and expertise of staff members, the type of reagents and infrastructural facilities available are major determinants of the quality of test results produced. Laboratory personnel, one and all, must strive for total quality assurance programme, seeing to it that every step of the testing process over which they have control is monitored and verified for accuracy and precision. Within the laboratory, the personnel must feel confident that they are protected from injury so that they can do their best work safely, without fear and distraction.
I. Salient Features:
Laboratory testing is the only way of diagnosing HIV infection.
In order to address critical issues, a separate laboratory services division was created in 2008. The division started by addressing concerns on technical and procurement issues related to HIV testing. As the importance of quality started to be recognised, steps were initiated to strengthen capacity of HIV testing through a unique structured and standardised training initiative. Technical support was provided to testing laboratories through the existing tier based network of referral laboratories at the apex (1), national (12) and state level (118).
The following objectives are therefore important to arrive at a successful laboratory diagnosis:
• Whom to test- one needs to be able to correctly suspect and screen a client at risk for HIV status.
• How to test i.e. the principles, procedures and the methodology of testing conforming to the objectives of testing and the national policy.
• How to interpret the test result- This refers to the collation and interpretation of the test results followed by the categorization of tested individuals into either HIV positive or HIV negative individuals. This is done by following the national policy of testing as prescribed by the government.
The role of the laboratory is very important and it is essential that the highest standards are not only maintained in each laboratory but are also regularly monitored.
There are a number of diagnostic procedures and various types of commercial diagnostic kits available. More over the results of the laboratory tests can be influenced by many factors. It is essential that each laboratory has a Standard Operating Procedure (SOP) which details each step of the test including bio-safety precautions. The laboratories are also expected to follow the national guidelines circulated by NACO on ethical issues related to HIV testing.
II. Tasks, Personnel and Structures
Laboratory Facilities across India working with DAC include employ and work with various personnel like TOs and Quality Managers at SACS, microbiologists at SRLs and NRLs, Lead Assessors, Laboratory Technicians, CD4 machine technicians and in-charges.
In addition to detection of HIV infection, their tasks cover ensuring biosafety in laboratories, collecting and transporting specimens for HIV testing, HIV testing at counselling and testing sites (ICTCs and PPTCTCs), quality assurance, laboratory tests for monitoring, staging and progression of HIV infection, counselling and HIV/AIDS testing and preventing occupational exposure and post exposure prophylaxis.
DAC assists the laboratories to carry out ICTC/CD4 Training, CD4 testing, quality assurance through internal quality control procedures, External Quality Assessment Scheme (EQAS), assessment of standards, viral load testing to support second line, national programme on early infant/child under 18 months diagnosis and capacity building to ensure that laboratories can efficiently provide services. The technicians and counsellors at the laboratories provides clients with pre-test counselling, taking written informed consent and collecting blood, giving reports to the client while maintaining confidentiality and with post-test counselling, following up a positive result by doing a CD4 cell count and then referring the client to an ART centre.