Numerous laboratory tests can be done in a private practice laboratory. Use of a commercial laboratory versus in-house testing should be evaluated to determine whether in-house testing is practical and economical. Because the availability of diagnostic laboratories and their reporting intervals may be problematic (eg, nights and holidays), performing some diagnostic screening tests in-house is often desirable. However, because the people performing these tests often have minimal technical training, quality control procedures must be rigorous. The time and care that must be devoted to quality control issues may preclude in-house testing in many practices. Errors may occur not only in testing procedures but also in sample collection and handling and in recording results.
Tests can be done using either manual or automated methods. Manual methods tend to be time consuming and are more subject to human error. Automated and semiautomated systems are available but are more expensive. Factors to be considered include instrument and reagent costs (including materials for calibration and quality control), availability of personnel training, technical support, and instrument maintenance and service. Although service contracts can cost up to 10% of the purchase price of an instrument, they are often cost-effective because of the expense of instrument repair.