The CFR requires verifying the chosen reference range (normal range) before reporting patient results. Each laboratory must have a reference range (normal range) for each analyte tested. The laboratory may adopt the manufacturer's reference range to fit the patient population. The reference range(s) must reflect the specimen type and demographics such as age and sex. If the manufacturer does not reflect the laboratory's patient population, the laboratory may use a published reference range(s). The laboratory must evaluate an appropriate number of specimens to verify each published reference range. The manufacturer or accreditation agency may recommend the number of samples, but the laboratory director will establish the correct number of samples to be analyzed. When the sample testing is completed, the results are analyzed. The standard used is that 95% of the samples tested fall within the reference range; the reference range may be utilized.
The reference range(s) may be adjusted with further study. The final approval for the evaluation process and the final ranges lies with the laboratory director.
