PIP: In Africa, funds available for drugs and other medical materials are usually inadequate, and what is available is often not spent well. This paper presents a list of laboratory reagents necessary for certain essential tests, based upon the average number of tests performed for 3.5 million patient contacts in church-related hospitals in Ghana. Data were derived from questionnaires regarding type and number of lab tests performed in 1981-1982, to which 23 hospitals responded. 25 tests were selected as essential. Frequently used techniques were analyzed and compared with methods recommended in standard references on the subject. Projections of amounts of chemicals incorporated a reserve to allow for individual differences and wastage. The recommended methods were selected on the basis of simplicity, low cost, reliability, and stability of reagents. Frequently performed tests include measurement of hemoglobin, malaria detection, and blood-glucose measurements. In choosing between chemical methods and reagent strips, the authors recommend strips, as it reduces the number of reagents and requires less expertise from hospital workers. The average number of tests performed are expressed per 30,000 out-patient consultations. Most district hospitals in Ghana treat 30,000-100,000 outpatients per year.