We have installed a new hematology analyzer. Assuming it passes our installation checks and comparison studies, is it acceptable to continue using the same patient reference range, or must this be re-established. If it must be re-established, what is the recommended procedure?

Transferring the references ranges from an established method to a new method/instrument yielding similar patient results (determined through a comparison study) is a legitimate approach provided it is acceptable to the director.

According to the January 24, 2003 CLIA regulations, laboratories using FDA-approved, unmodified, nonwaived tests introduced on or after April 24, 2003 must verify the method performance specifications (below) before placing into routine use and these characteristics include: accuracy, precision, reportable range of test results for the test system, and identification of reference intervals (normal values) appropriate for the laboratory’s patient population.

Note: CMS’ Appendix C (SOM), Survey Procedures and Interpretive Guidelines for Laboratories and Laboratory Services, under §493.1253 (b)(1)(ii), states: The laboratory may use the manufacturer’s reference range provided it is appropriate for the laboratory’s patient population. Practically, this means that the laboratory director conscientiously selects the reference range(s) to use whether they be from the manufacturer, literature sources, or making the selection through evaluating patients’ results as to whether they “make sense” in the context of patients’ diagnoses. The decision must be documented.

Note that CAP, The Joint Commission, and COLA requirements essentially parallel these approaches. Of course, an actual reference range study also could be conducted. Estimation of reference intervals is time-consuming and costly. Typically, it is recommended to have 120 healthy individuals for each group, and, if there are male and female subgroups, then 240 specimens are needed. Guidelines for reference value studies can be found in Tietz’s Textbook of Clinical Chemistry and in CLSI’s guideline, C28-A3, Defining Laboratory, Establishing, and Verifying Reference Intervals in the Clinical Laboratory.

However, if the FDA-approved tests are modified and in-house developed tests, the reference range must be established.

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