External Quality Assessment Scheme (EQAS)

External quality assessment scheme (EQAS) is a powerful tool that challenges internal quality control measures adopted by any laboratory. The National AIDS Control Organization (NACO) has implemented the EQAS under Phase III of National AIDS Control Program to bring qualitative improvement in blood banks and human immunodeficiency virus (HIV) testing laboratories. The coded samples received from the state reference laboratory (SRL) were subjected to two rapid tests with different principles and one enzyme linked immunosorbent assay (ELISA) test. In addition, 20% of all HIV reactive and 5% of all HIV nonreactive samples collected and tested by ELISA in the 1st week of every quarter were sent for cross-checking to the SRL.

Under the national external quality assessment scheme, the HIV testing laboratories have been categorized into four levels: Apex laboratory, national reference laboratories, SRLs, and district level (integrated counseling and testing center [ICTC] and blood banks). The ICTC and blood banks are monitored by the designated SRLs. All ICTCs participate in an EQAS and have been assigned an SRL. Under EQAS, each ICTC receives coded samples from the reference laboratories twice a year for testing. ICTCs also send 20% of all positive samples and 5% of all negative samples collected in the 1st week of every quarter for cross-checking to the SRL.

Samples for proficiency testing or EQAS should be treated exactly as the patient samples. Only then the true situation in the laboratory can be found and fixing the problem becomes easy. The authors attributed discordant results to equipment problems and low sensitivity of kits. EQAS measures the accuracy or bias of results and stability of laboratory testing methods. It also gives the laboratories, both the management and technical staff, added confidence in their test results. It helps to maintain public confidence in a facility and provides scope for continuous improvement. External quality assessment scheme is an early warning system that identifies target areas where immediate intervention is needed including training needs of laboratory personnel.As a participating laboratory, we have tried to improve our laboratory practices by regular quality control of test kits, procedure and equipment.

The EQAS was set up to ensure high reliability and validity to the HIV and CD4 tests under the programme and higher levels of proficiency testing. Each NRL has attached SRLs for which it has the responsibility of supervision. Each SRL, in turn, has ICTC which it monitors. One Technical Officer at each SRL is supported by funds from NACO to facilitate supervision, training and continual quality improvement in all SRLs and linked ICTCs. EQA for HIV is done in two ways:

  • Panel Testing
  • Re-testing/ Reverse Testing:
Under External Quality Assessment Scheme (EQAS) programme, all ICTC/PPTCT Centers are linked with State Reference Laboratory in JIPMER, Department of Microbiology. As per the programme structure of External Quality Assessment Scheme, all ICTC/PPTCTs LT’s participate in the EQAS programme. The Programme is being conducted twice in a year for all ICTC/PPTCTs in the Union Territory of Puducherry. During the EQAS programme panel of samples is provided to all Centers to check the quality of Laboratory. All ICTC/PPTCTs report to SRL within 7 days of receiving the coded samples to check the level of concordance. Simultaneously all ICTCs (F-ICTCs & PPP-ICTCs) also send 20% of positive serum sample and 5% of negative serum samples collected in every quarter to SRL for cross – checking.