How to choose a clinical chemistry analyser for a Kenyan hospital laboratory

The first number most laboratories look at is tests per hour, and it is the number most likely to mislead. A manufacturer states throughput at constant speed for single and double-reagent items under ideal conditions. A modern benchtop chemistry analyser cS-T240, for example, is rated at 240 tests per hour at constant speed and up to 360 tests per hour with the ISE module running alongside the photometric channels.

Those figures are accurate — and they describe a workload that few district laboratories actually present. The same analyser runs at 120 tests per hour minimum when the cross-contamination avoidance function is active, and at 80 tests per hour for prediluted samples. A laboratory doing substantial paediatric or cerebrospinal fluid work, where predilution is routine, will not see the headline number and should not budget on it.

The useful exercise is to count real samples over a fortnight, separate them by type, and apply the throughput that matches each. That produces a realistic daily capacity, and it usually shows that a mid-range analyser is sufficient where a larger one was being considered.

Throughput determines how fast samples move. Onboard capacity determines how often a technologist has to stop and reload. The CS-T240 holds up to 60 colorimetric items and 3 ISE items simultaneously, which covers a routine hospital menu — liver and renal panels, lipids, glucose, electrolytes, cardiac markers and specific proteins — without interruption between runs.

Where a laboratory offers a narrower menu, that capacity is spare. Where it offers specialist assays alongside routine work, the capacity is what makes a single-analyser configuration workable instead of forcing a second instrument.

Method flexibility matters for the same reason. Rate assay, end-point assay and two-point assay support means assays can be configured as the menu grows, rather than the menu being limited to what the analyser was shipped with.

An analyser produces results only while its reagents are on the shelf. This is where laboratory equipment projects most often fail in East Africa — not at purchase, but four months later, when a reagent lot is delayed and the instrument sits idle while samples are referred out.

Before signing, establish three things: whether the reagent system is held in local stock or imported per order, what the reorder lead time is, and whether controls and calibrators come from the same source. A closed system with reliable local supply is more useful than an open system whose reagents arrive unpredictably.

It is worth asking the supplier directly how many of that analyser model they already support in the country. Instruments with an installed base have a parts and reagent pipeline behind them; a first installation does not.

Chemistry analysers are sensitive to power quality, ambient temperature and water quality. A site assessment before delivery should cover stable power with appropriate conditioning, room temperature control, bench loading, and — for analysers requiring it — a water supply meeting the manufacturer's specification.

These are inexpensive to address before installation and disruptive to address afterwards. A supplier who delivers without assessing the room is transferring that risk to the laboratory.

A quotation for an analyser should state more than the instrument price. Require the reagent and consumable list with unit costs, the warranty period and what it covers, the installation and commissioning scope, applications training for the laboratory staff, and the preventive maintenance schedule with the cost of an annual contract.

Quoted this way, two analysers can be compared on cost of ownership rather than purchase price — which frequently reverses the apparent ranking.