Costs are described in a number of ways. For example, they can be direct or indirect and fixed or variable. Direct costs are those that are directly traceable to a test procedure such as reagents, controls, and testing personnel. Indirect costs are costs not directly traceable to a test procedure such as general operation activities and institutional costs such as clinical laboratory management, heat, lighting, housekeeping, etc.
Fixed costs are those that do not vary (for a given time period) with changes in the test volume, whereas variable costs change proportionally with changes in test volume. The cost of a testing instrument is a fixed cost; reagents, controls, and disposable supplies constitute variable costs.
Table 1 illustrates the various cost categories:
|Table 1: Cost Determination|
| Direct costs – attributed to an individual test |
Reagents, personnel performing test, calibrators, proficiency testing
| Indirect costs – not attributed to an individual test |
Housekeeping, electrical use, building maintenance, HVAC
| Fixed costs – constant and not subject to test volume |
Test instrument, accreditation, non testing personnel i.e. managers and secretaries
| Variable costs – changes based on test volume |
Reagents and disposables
Labor for testing may be fixed or variable, but is generally considered to be a fixed cost unless new personnel are hired or overtime is required to perform the testing. For example, if there are salaried personnel hired to do the entire laboratory testing during a specific time period (i.e. 8-hour day) their contribution to perform that specific test becomes fixed.