Instrument Validation and Verification Under CLIA (493.1253)
Under CLIA §493.1253, a lab must establish or verify performance specifications before reporting patient results on a new nonwaived test. For an unmodified FDA-cleared or approved test, verify accuracy, precision and reportable range, and confirm the reference intervals. Modified tests and LDTs also need analytical sensitivity, specificity and interference studies.
Key facts and official sources
Regulation: 42 CFR 493.1253. It applies to tests the lab introduces after April 24, 2003.
Calibration and calibration verification: §493.1255
The lab must document all verification and validation activities.
Verification: unmodified FDA-cleared or approved tests
Accuracy
Precision
Reportable range
Confirmation that the manufacturer's reference intervals fit your patient population
Validation: modified tests, LDTs, and tests without FDA clearance
Accuracy
Precision
Analytical sensitivity
Analytical specificity, including interfering substances
Reportable range
Reference intervals
Any other characteristic needed for test performance
Validation checklist
Written verification or validation plan approved by the director
Acceptance criteria defined before data collection
Comparison samples and materials documented
Data, statistics and a conclusion for each characteristic
Calibration and control procedures set
Director sign-off before patient testing starts
Staff trained and competency documented
How SLC helps
SLC plans and documents instrument validations and method verifications for clinical labs nationwide. This includes new analyzers, test menu expansions, and LDTs. Related: Method verification and calibration verification, LDT validation, NGS assay validation, QMS.
FAQs
What is the difference between verification and validation? Verification confirms the manufacturer's claims in your lab. Validation establishes performance for a modified test or LDT.
Do waived tests need §493.1253 verification? No. It applies to nonwaived tests. Waived tests follow manufacturer instructions.
Who approves the study? The laboratory director, before patient results are reported.
Do I re-verify when moving an instrument? Many labs do limited checks after relocation or major repair. Base the scope on risk and manufacturer guidance.
How often is calibration verification required? At least every 6 months and after certain events, unless §493.1255 exceptions apply.
Can a second identical analyzer share data? Each test system needs documented performance. A comparison between instruments is common.
Work with Sound Lab Consultants
Sound Lab Consultants (SLC) is a clinical laboratory consulting company. It provides CLIA compliance, lab startup and licensing, quality management, laboratory director and consultant personnel, and deficiency resolution services to labs nationwide. SLC works with labs accredited by CAP, COLA and The Joint Commission and prepares them for those inspections. Mailing address: PO Box 2135, Chandler, AZ 85244.
Last reviewed Oct 2026 · Sound Lab Consultants CLIA team · General information, not legal advice.