Human immunodeficiency virus (HIV) infection may lead to the development of immunological responses that make laboratory support critical in all areas of diagnosis and management. Diagnosis of HIV infection cannot be established by means other than serological testing, and CD4 lymphocyte count is a prerequisite for the initiation of antiretroviral therapy (ART) and for monitoring treatment outcomes.
The role of the laboratory in HIV infection prevention and intervention strategies is increasingly being recognised especially in the implementation and monitoring of ART in resource-poor countries. The capacity of laboratory services will therefore need to be strengthened to cope with the scaling up of HIV intervention programmes and provide support for the response to HIV/acquired immune deficiency syndrome (AIDS).
Zambia in sub-Saharan Africa has a high HIV/AIDS disease burden with high morbidity and mortality due to the disease. Thus, the ART intervention programme has become a priority in the management of HIV/AIDS using antiretroviral drugs. Since 2004, Zambia has been rolling out and scaling up access to ART in accordance with World Health Organization (WHO) guidelines. Currently, there are 246 ART centres in the public sector across the country, but only 57 (23%) centres have laboratory services that provide full diagnosis and monitoring for HIV/AIDS patients on ART. Furthermore, the distance between some laboratories and ART centres is not in accordance with WHO guidelines.
Consequently, in many situations clinicians have had to stage and manage patients according to WHO staging guidelines, without laboratory support or evidence. In addition, the ART is often given to patients without performing monitoring tests for response and toxicity to therapy. This poses a risk to some HIV/AIDS patients on ART to develop pathophysiological damage and drug resistance.
Turnaround time study
A small turnaround time study aimed to quantify the time taken for CD4 lymphocyte count results to reach the ART clinics. This is one of the major challenges in scaling up and strengthening quality assured services for diagnosis and monitoring tests for HIV/AIDS patients on ART in Zambia.
The work was undertaken during 2007 and the design was a descriptive cross-sectional survey of public ART centres. However, only 78/137 (57%) responded to the survey. In order to increase the value of the survey, three reminders were sent to each ART clinic that did not respond within a two-week period to ensure that all identified ART clinics were included in the survey.
Data were collected using a number of research tools designed to solicit information from eligible respondents in all public ART institutions, and one-to-one interviews were employed where possible. Respondents to the survey included laboratory staff and clinicians.
Study findings
Clearly, availability of equipment on which to perform CD4 lymphocyte counts is critical to ongoing diagnosis of HIV/AIDS in the sub-Saharan setting, in order to initiate appropriate therapy and monitor its effects.
According to WHO guidelines, turnaround time for CD4 count results to reach ART centre should be within 12 hours, especially where laboratory services are located in the same hospital as the ART centre. Unfortunately, this has not been achieved due to the lack of equipment and a shortage of laboratory staff.
The study findings on turnaround time indicate that 19% of the ART clinics received results the same day (within 12 hours), 34% received results the next day, 33% received results after more than two days, and 9% of ART clinics received results after more than a week. This applied to ART centres with and without laboratory facilities on site. (Fig 1).
Turnaround time for CD4 lymphocyte count results in Zambia is affected by a number of factors, which include storage and transportation of blood samples to the referral laboratory. Furthermore, pathology facilities have inadequate laboratory staff members, reagents and supplies, and suffer frequently equipment breakdowns and electricity shutdown – a recurring problem in sub-Saharan Africa. This is further compounded by high a patient:clinician ratio.
According to a 1992 Zambian Ministry of Health reform vision, the country aimed to improve the health status of all its citizens through equality of access to cost-effective healthcare as close to the family as possible. The findings of the present study clearly indicate that, in terms of laboratory support for ART services, equality of timely access to CD4 count results is not available (Fig 1).
Reaction to delay
It is clear from the findings of the present study that there is considerable variation in turnaround time for CD4 counts in Zambia. Prolonged results turnaround time delays the initiation of ART in appropriate patients and the monitoring of HIV/AIDS patients’ reaction to drugs. It also affects the assessment of HIV drug resistance.