Utilization of Rapid Diagnostic Testing in sub-Saharan Africa: Challenges and Effects on HIV Prevention

Inaccuracy of RDT Results

A major issue with the utilization of RDTs in HIV diagnosis in SSA is their inaccuracy, poor sensitivity and specificity, and high rates of false HIV positive results. Sensitivity of RDTS is the probability of getting an HIV positive test result when the disease is truly present, and specificity is the probability of getting a negative test result when the disease is truly absent.21 The score of these variables range from 0-100%. According to the WHO, HIV- RDTs should have a sensitivity of at least 99% and a specificity of at least 98%.22 The results of a study conducted by researchers on the utilization of Determine, a commonly used HIV-RDT in Cameroun, showed a sensitivity result of 100% and only a 91.5% specificity.23 However, when the samples were retested, 129 of the 295 people who were initially diagnosed as HIV-positive, were actually HIV-negative.23 A similar situation occurred in Uganda. In the Rakai district of Southwestern Uganda, an area with high HIV prevalence, three of the most commonly used HIV-RDTs (Determine™, STAT PAK^®, and Uni-Gold™) revealed critical inaccuracies in results. About 45% of patients who received HIV positive results received them in error.23

HIV Misdiagnosis

Results from HIV-RDTs can sometimes be difficult to interpret, especially when tests lines or bands are faint. In such cases, results are left to the subjective interpretation of testers, which most often leads to false positive HIV diagnosis. In a recent assessment of HIV-RDT administration in South Africa,24 issues with subjective interpretation of results were identified.25 This led to the misdiagnosis of some patients. In another incident that occurred between 2004 and 2005, Médecins Sans Frontières (MSF) staff offering HIV-RDTs in SSA, misdiagnosed 44 people in the Democratic Republic of Congo, Burundi, and Ethiopia with HIV.26

Tester Capacity

Low staff capacity, coupled with high workload, and the lack of comprehensive quality management systems, have been found to contribute to HIV-RDT result errors.27 While the number of people receiving HIV-RDTs in SSA has significantly increased in the past few years, the number of health personnel available to administer these tests has not increased proportionally. Of those available to offer the service, several have not been adequately trained on how to adhere to standard operating procedures and to maintain quality assurance such as tester competency, pre-test preparations, quality control, and record keeping.28 Inadequate staff training in HIV-RDT methodology is costly. This is because it can negatively affect testing accuracy. The results of a study conducted in South Africa showed that the sensitivity and specificity of HIV-RDTs performed by lay nurses and counsellors were 92.5 – 97.3% and 97.6 – 98.2% respectively, while those performed by trained laboratory technicians showed a 100% performance. 28 The researchers concluded that the inadequate training of lay nurses and counsellors may have contributed to the discrepancies and difficulties in the interpretation of RDT results. 28 Several other HIV-RDT studies conducted in SSA also identified lack of adequate tester testing capacity to be responsible for some of the false positive and negative HIV diagnosis.

Poor HIV RDT Kit Storage

HIV-RDTs are to be stored at ambient temperatures specified by manufacturers (36°- 86° F or 2-30°C) and used before their expiration dates. 28 Yet, in some SSA countries, HIV-RDTs are stored in suboptimal conditions and those nearing expiration, are not discarded. This affects the quality and accuracy of test results. Researchers of a quality assurance study conducted to test the effects of higher than manufacturer-specified temperatures for three HIV-RDTs (OraQuick, Determine 1/2^™ and Uni-Gold™) on 378 participants at Ndirande Health Centre in Blantyre, Malawi, found seven false HIV negative results among test kits that were stored at suboptimal temperatures.29 Facente et al also found a significant decline in test specificity of OraQuick ADVANCE^® tests that were used a month after expiration.30

Testing Credibility

Poorly trained and inexperienced staff have the tendency to increase the likelihood of inaccurate interpretation of HIV-RDT results.23 Inaccurate results can lead to low HIV testing uptake, negate the goal and credibility of HIV-RDTs, and create missed opportunities for linking HIV positive people to care and prevention services.23 Inaccurate results can also cause the unintentional transmission of HIV to previously uninfected people. 23 As HIV-RDT testing technology is rapidly evolving and is frequently utilized in SSA, appropriate health personnel need to be trained, certified, and provided with routine support and supervision to ensure that testing procedures are followed correctly, and results are accurately interpreted. They also need to be trained in quality assurance, so they can ensure that expired kits are not used. Doing this will increase public trust and confidence in the technology.

To increase their efficacy and accuracy, HIV-RDT kits need to be stored at prescribed temperatures, and those nearing expiration need to undergo quality control checks before they are used. When it comes to temperature, it can be monitored by placing thermometers in storage areas where the kits are stored. This will enable site supervisors to surveil storage temperature ranges and to preserve kit quality. Temperature control logs can be posted outside storage areas so readings can be checked and recorded daily. Investing in proper storage protocols and facilities will ensure that manufacturer recommended instructions are observed. This will minimize false HIV diagnosis and wastage.

Social, Emotional, and Economic Consequences

The social and emotional consequences of a false HIV positive diagnosis can be severe and more difficult to handle than the physical effects of the infection. A false positive HIV result can put people at risk of physical and verbal abuse, abandonment, and ostracization by friends, family, and community members.³³ These outcomes are disproportionately higher among women, as they are more likely than men to access health care facilities and to be tested for HIV. In addition to psychological trauma, an HIV misdiagnosis can also lead to unnecessary ART initiation and stigma. Some researchers who conducted studies on the effects of false HIV positive diagnosis on people found that it led to divorce, the incurring of unnecessary expenses due to clinical visits, and physical harm in some communities in the Democratic Republic of Congo, Burundi, Ethiopia,26 and Ghana.14

To address the socio-economic and emotional consequences associated with the inaccurate interpretation of HIV-RDT results, health workers need to work with a “second-reader” to validate test results when they are unsure before pronouncing a diagnosis. Retesting also needs to be done as part of routine service prior to putting people on ART. This will help to save people falsely diagnosed from debt and financial ruin.