Quality Control Ranges -Use Of Manufacturer's Ranges
Can the manufacturer's stated ranges be used as the laboratory's quality control ranges?
Any examples are for illustrative purposes only.
The standards require each laboratory to establish its own control ranges through repetitive testing. However, there is an allowance to use manufacturers' ranges when all of the following conditions are met:
It is at the determination of the Laboratory Medical Director to approve quality control ranges after giving consideration to the clinically significant variance as compared to the statistically derived SD.
The standards require each laboratory to establish its own control ranges through repetitive testing. However, there is an allowance to use manufacturers' ranges when all of the following conditions are met:
- the stated values correspond to the method and instrument used by the laboratory,
- the mean obtained by the laboratory reflects the manufacturer's stated mean, and
- the Laboratory Medical Director assures the range are narrow enough to detect clinically significant errors.
Manufacturers' ranges may also be implemented if a test is used so infrequently that calculation of valid statistics is not possible. In settings where there is a high precision due to precise instrumentation and/or limited testing personnel, the laboratory's own calculated standard deviation (SD) may be very small. The manufacturer's ranges may span more than the commonly used +/-2 SD. Using the laboratory's calculated +/-2 SD may produce unnecessarily narrow ranges, causing the testing personnel to frequently repeat QC and investigate when the controls perform outside the laboratory's range but within the manufacturer's range. Alternatively, the full manufacturers' ranges may be too broad to promote the detection of clinically significant error. Selection of the appropriate range is a balance between these two ends of the spectrum.
It is at the determination of the Laboratory Medical Director to approve quality control ranges after giving consideration to the clinically significant variance as compared to the statistically derived SD.
Manual:
Laboratory
Chapter:
Quality System Assessment for Nonwaived Testing QSA
First published date: April 11, 2016
This Standards FAQ was first published on this date.
This page was last updated on October 28, 2021