Download 206 TB Verifying and Establishing Acceptable Ranges for a New Lot

Issue: #206
Date: April 6, 2016
Verifying and Establishing Acceptable Ranges for a New Lot of
Quality Control Material
WHY: CLIA requires laboratories to verify or establish acceptable control ranges as stated in the Control Procedure
Standard 493.1256 (d)(10)(i-iii):
The laboratory must establish or verify the criteria for acceptability of all control materials.
(i) When control materials providing quantitative results are used, statistical parameters (for example, mean and
standard deviation) for each batch and lot number of control materials must be defined and available.
(ii) The laboratory may use the stated value of a commercially assayed control material provided the stated value
is for the methodology and instrumentation employed by the laboratory and is verified by the laboratory.
(iii) Statistical parameters for unassayed control materials must be established over time by the laboratory
through concurrent testing of control materials having previously determined statistical parameters.
Note: The laboratory user should routinely read the control package insert to ensure ongoing compliance with
manufacturer instructions. Manufacturers of control material direct the laboratory user to follow specific protocols,
including 1) storage and stability, 2) reconstitution instructions, and 3) assignment of values. Control materials
must be treated exactly as instructed by the manufacturer so they reliably provide the intended use of monitoring
test system performance. Most manufacturers of assayed controls have wording similar to the following in their
package insert: “For routine use it is recommended that each laboratory establishes its own means and
acceptable ranges and use the published ranges as a guide”. If the manufacturer of an assayed control
recommends that each laboratory establishes its own means and acceptable ranges, than the lab must do so.
WHEN: For all new lots of quality control material.
HOW: Before the current working control lot number is depleted or expired, verify or establish acceptable control ranges
through concurrent testing of new and in-use control materials. Read the manufacturer control package insert of the new
lot to ensure correct application of the protocol.
Verifying Acceptable New Lot Quality Control Ranges
1.
2.
3.
4.
5.
Document the method/instrumentation-specific quality control ranges from the manufacturer’s QC package insert
on the attached QC Verification Log. This is the range of values that the QC results should fall within when the
test system is functioning properly.
Perform concurrent testing of control materials by running the new lot of control materials following the acceptable
performance of the current QC.
Test the new lot of control materials a minimum of 5 times per level over several days using more than one
operator. If this is not possible, multiple determinations can be performed within the same day.
Record results of the new lot of control material on the QC Verification Log.
Compare the results of the new control with the manufacturer’s expected control range.
 If the new control results are within range, the new lot number of control has been verified and can be put
into use when the current control lot is depleted or expired.
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TLC Technical Bulletin #206

6.
7.
8.
If any of the new control results fall outside of the manufacturer’s range, perform corrective action to
determine why the control is not performing as expected. Confirm by repeat analysis.
Have the laboratory director or designated technical personnel review and approve the verification study.
Record “in use” date on manufacturer’s QC package insert. Retain the QC package insert and verification study
for two years.
Use the manufacturer ranges as a guide in setting the initial control limits. Once a statistically relevant amount of
control data (20 or more per level) is available, go to procedural step 3 of Establishing Acceptable Quality Control
Ranges.
Establishing Acceptable New Lot Quality Control Ranges
Perform concurrent testing of control materials, by running the new lot of control materials following the
acceptable performance of the current QC. Test all levels of controls a minimum of 20 times per level over a
period of two weeks using more than one operator.
3. Calculate the following statistical parameters from the data for each control level after ensuring that all erroneous QC
data points are excluded. If you require a calculator to perform these calculations one can be found online at
http://tools.westgard.com/qccalculator.html
a. Mean
b. Standard Deviation (SD)
c. Coefficient of Variation (CV)
4. Evaluate the statistics: – Determine if the difference between the calculated mean and the expected manufacturer
mean is acceptable. The new mean should be within 1 SD of the manufacturer’s mean. If not, consult the QC
manufacturer and/or the test system manufacturer to determine if instrument troubleshooting is necessary.
5. Compare the calculated CV to your previous lot’s historic CV for each analyte and QC level. (Note: historic CV
represents the precision of the specific test system and control level over time. Six months is generally an adequate
time frame to establish the historic CV). If your calculated CV is less than or not significantly more than your historical
CV then you should use the historical CV for the calculations in step 6 found below. If your calculated CV is
significantly higher than your historical CV then consult your test system manufacturer to determine if instrument
troubleshooting is required.
a. If historical data is not available for your laboratory, TLC recommends contacting the QC manufacturer to
obtain interlaboratory peer group data for the lot you are using. The cumulative peer group CV can be used
in place of historical data in this case.
b. If you participate in a interlaboratory peer group QC program, review the cumulative peer group CV for each
analyte to determine if the CV you have calculated in step 5 is acceptable.
6. Calculate a second SD based on the historic CV you have chosen in step 5.
a. SD = Historic CV /100 x Current New Mean
7. Establish control ranges from the new mean and calculated SD.
a. Determine the 2SD control ranges by multiplying the calculated SD by 2, than add and subtract this result
from the mean.
b. Determine the 3SD control range by multiplying the calculated SD by 3, then add and subtract each result
from the mean.
8. Approval - Have the laboratory director or designated technical personnel review and approve the new control
ranges.
9. Record the “in use” date on the manufacturer’s QC package insert or if control has been in use, document date of
QC range adjustment. Retain the QC package insert and statistical data for two years.
10. Enroll in an interlaboratory peer group program, when available, and submit data on a monthly basis (if not already
enrolled). This report should be used to monitor your QC statistical parameters and aid in monthly evaluation of your
QC test data.
1.
References:
1
CLIA Regulation, Appendix C-Interpretive Guidelines, 493.1256(d) (10)(i-iii): Standard: Control procedures.
www.cms.hhs.gov/clia
2
COLA guidelines: QC 8 R & QC 10 R
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All Rights Reserved
2
QC VERIFICATION LOG
Control Name:
Level:
Level:
Level:
Lot No:
Lot No:
Lot No:
Exp Date:
Exp Date:
Exp Date:
QC Dates/Initial:
QC
Level
Manufacturer
(Mfg)
Range
Analyte
QC Results
Problem Areas:
Corrective Action:
Reviewed by:
Follow up to be done:
Date:
Are ALL
results
w/in mfg
range?
Verified for
Reviewed
use?
by:
(Yes or No)