Calibration and Calibration Verification
Information to assist your laboratory in meeting this CLIA requirement for nonwaived (moderate and high complexity) test systems!
NOTE: On January 24, 2003, the Centers for Disease Control and Prevention (CDC) and the Centers for Medicare & Medicaid Services (CMS) published laboratory regulations (CLIA) that became effective April 24, 2003. A summary of updated requirements pertaining to calibration and calibration verification is included in this brochure. However, this brochure is not a legal document. The official CLIA program provisions are contained in the relevant law, regulations and rulings. For more complete information, you may access the regulations on the Internet at http://www.phppo.cdc.gov/CLIA/regs/toc.aspx.
What is the difference between calibration and calibration verification?
Calibration is the process of testing and adjusting the instrument or test system readout to establish a correlation between the instrument’s measurement of the substance being tested and the actual concentration of the substance.
Calibration verification means testing materials of known concentration in the same manner as patient specimens to assure the test system is accurately measuring samples throughout the reportable range.
No, the CLIA requirements for calibration have not changed. The laboratory is responsible for performing calibration as directed by the manufacturer’s test system instructions, and when calibration verification of the test system (see below) does not produce acceptable results.
Reminder: Be sure to document in the laboratory’s records each time you perform calibration.
No, calibration is not required for the following:
The test system’s instructions should describe the process for performing calibration, as well as when and how often it is to be performed.
The test system’s instructions should specify the number, type and concentration of the calibration material to use.
Calibration material is a solution that contains a known amount of analyte. In the past, the term “standard” was generally used to mean calibration material.
No, the laboratory has always been responsible for calibration verification or “checking” calibration. However, the process for checking a moderate complexity test system's calibration was not defined. The regulations now describe how and when calibration verification is to be performed for nonwaived (moderate and high complexity) tests.
Reminder: Be sure to document in the laboratory’s records each time you perform calibration verification.
When must I check a test system’s calibration (perform calibration verification)?
Once every 6 months (or more frequently if specified in the test system’s instructions) and whenever any of the following occur:
Reminder: The laboratory is responsible for verifying calibration on factory-calibrated test systems that cannot be calibrated by the user.
A variety of materials with known concentrations may be used to verify calibration, for example, commercially available standards or calibration materials, proficiency testing samples with known results, control materials with known values, or patient specimens with known values.
Since the purpose of calibration verification is to check whether the test system is providing accurate results throughout the reportable range, three levels should be tested–one at the high end of the reportable range, one at the low end of the reportable range, and one near the midpoint of the reportable range.
Clinical Laboratory Yes, there are exceptions:
If calibration verification results are unacceptable, you must repeat the test system’s calibration procedure. After repeating the calibration procedure, it is good laboratory practice to run controls before resuming patient testing.
If the test system is factory-calibrated, consult with the manufacturer of the test system.
No. The CLIA calibration and calibration verification requirements are the same CLIA requirement for nonwaived test systems.
Refer to “The State Operations Manual,” Appendix C–Interpretive Guidelines, Calibration and calibration Verification Procedures (§493.1255) available on the CMS website at: www.cms.hhs.gov/clia.
Links to other laboratory-related resources can be found at these websites:
FDA: www.fda.gov/cdrh/CLIA/index.html (for a listing of waived, moderate complexity and high complexity tests).
CMS- 2226-F: 42 CFR 493 Medicare, Medicaid, and CLIA Programs; Laboratory Requirements Relating to Quality Systems and Certain Personnel Qualifications; Final Rule on January 24, 2003, with an effective date of April 24, 2003.
Subpart K, Part 1, Quality System for Nonwaived Testing; General Laboratory Systems, Preanalytic Systems & Analytic Systems, Section 493.1255(b):
Standard: Calibration and calibration verification procedures
(b) Perform and document calibration verification procedures –
(b)(1) Following the manufacturer’s calibration verification instructions;
(b)(2) Using the criteria verified or established by the laboratory under Section 493.1253(b)(3) –
(b)(2)(i) Including the number, type, and concentration of the materials, as well as acceptable limits for calibration verification; and
(b)(2)(ii) Including at least a minimal (or zero) value, a mid-point value, and a maximum value near the upper limit of the range to verify the laboratory’s reportable range of test results for the test system; and
(b)(3) At least once every 6 months and whenever any of the following occur:
(b)(3)(i) A complete change of reagents for a procedure is introduced, unlessthe laboratory can demonstrate that changing reagent lot numbers does not affect the range used to report patient test results, and control values are not adversely affected by reagent lot number changes.
(b)(3)(ii) There is major preventive maintenance or replacement of critical parts that may influence test performance.
(b)(3)(iii) Control materials reflect an unusual trend or shift, or are outside of the laboratory’s acceptable limits, and other means of assessing and correcting unacceptable control values fail to identify and correct the
(b)(3)(iv) The laboratory’s established schedule for verifying the reportable range for patient test results requires more frequent calibration verification.