Clinical chemistry in district laboratories

The clinical chemistry tests performed in district laboratories will depend on:

1. ▪ The health needs of the community and the requirement for clinical chemistry tests to assist in disease diagnosis and prognosis, monitoring of treatment, and screening to prevent ill-health.

2. ▪ The training and experience of laboratory staff and the support that can be provided by the district laboratory coordinator to ensure clinical chemistry tests are performed correctly with adequate control and safety.

3. ▪ Whether the appropriate equipment is available and affordable (purchasing and running costs) and can be maintained by the user.

4. ▪ Whether the required chemicals and products to make reagents, standards, and controls are available and affordable, and whether the more complex reagents can be provided to district laboratories in ready-made form or in easy to prepare packs that have sufficient stability.

5. ▪ Whether the laboratory has access to or can make its own supply of chemically pure water (see subunit 4.4).

6. ▪ Whether the numbers of tests performed are sufficient to avoid reagents, standards, and controls from being wasted due to their expiry. In some situations it may be possible and more appropriate to send patients’ samples to a larger laboratory for clinical chemistry tests.

Since the publication of the first edition of Part 1 District Laboratory Practice in Tropical Countries the essential role of the laboratory in providing a scientific foundation for district health care and improving the quality of health care to communities, has not changed. The new challenges faced by health authorities however, have led to changes in laboratory practice and a greater emphasis on the need for reliable well managed district laboratories and their rational use in district health care.

In deciding the changes to be incorporated in the new edition of Part 1, the author and those who have helped with the revision have been guided by the views and requests of those using the book in their work and training programmes. The important chapters covering management, quality assurance, health and safety and equipping of district laboratories have been reviewed and updated where needed. For those with internet access and e-mail facilities, the details of equipment manufacturers now include website information and e-mail addresses.

Information on parasitic diseases and their control has been brought up to date. Current knowledge on HIV interaction with parasitic pathogens and new technologies to diagnose parasitic infections have been included. Immunochromatographic tests to diagnose malaria have been described, their limitations discussed, and information on the WHO malaria rapid diagnostic tests website included. Other parasite-related websites and a list of up to date references and recommended reading are given at the end of the parasitology chapter.