Are physicians' office laboratory results of comparable quality to those produced in other laboratory settings?

In 1995, California adopted a bill that brought laboratory laws in line with the 1988 Clinical Laboratory Improvement Amendments' standards for clinical laboratories and mandated a study comparing results in physicians' office laboratories (POLs) with other settings.

To determine whether persons conducting tests in POLs produce accurate and reliable test results comparable to those produced by non-POLs.

Survey of clinical laboratories using proficiency testing data.

All California clinical laboratories participating in the American Association of Bioanalysts proficiency testing program in 1996 (n=1110).

"Unsatisfactory" (single testing event failure) and "unsuccessful" (repeated testing event failure) on proficiency testing samples.

The unsatisfactory failure rate for POLs was nearly 3 times (21.5% vs 8.1%) the rate for the non-POLs and about 1.5 times (21.5% vs 14.0%) for POLs that used laboratory professionals as testing or supervisory personnel (P<.001). The POL unsuccessful rate was more than 4 times (4.4% vs 0.9%) the rate for non-POLs and more than twice (4.4% vs 1.8%) the rate for the POLs using laboratory professionals (P<.001).

Significant differences exist among POLs, POLs using licensed clinical laboratory scientists (medical technologists), and non-POLs. Testing personnel in many POLs might lack the necessary education, training, and oversight common to larger facilities. We must better understand the contributing factors that result in the poorer results of POLs relative to non-POLs. In the meantime, patients should be aware that preliminary findings suggest that differences in quality of laboratory tests based on testing site may exist. Laboratory directors at all testing sites must ensure that they understand laboratory practice sufficiently to minimize errors and maximize accuracy and reliability. Directors must understand their obligation when they elect to oversee those assigned testing responsibility. Legislators may wish to reconsider the wisdom of further easing restrictions on those to whom we entrust our laboratory specimens.