Article from Dr. George Anastasopoulos
Intermediate checks—quick, periodic performance verifications conducted between full calibrations—are a critical but often overlooked requirement in ISO/IEC 17025. Unlike full calibrations, these checks provide ongoing assurance that equipment remains accurate, reliable, and fit for use.
Dr. Anastasopoulos explains that ISO/IEC 17025:2017 explicitly requires labs to establish procedures for intermediate checks (clauses 6.4.10 and 7.7.1). The frequency must be determined through a risk-based approach, considering factors such as equipment stability, usage, environmental conditions, and potential consequences of inaccurate results.
Key takeaways:
- Intermediate checks ≠ internal calibrations — they are faster verifications, not full recalibrations.
- They cannot be replaced by proficiency testing (PT) or interlaboratory comparisons (ILCs)—they serve a distinct, complementary role.
- Proper planning, documentation, and recordkeeping are essential to demonstrate compliance during audits.
- Benefits include early detection of drift, reduced risk of invalid results, stronger audit evidence, and greater client confidence.
Ultimately, neglecting intermediate checks risks nonconformities, reputational damage, and compromised measurement integrity. When performed and documented correctly, they are a powerful tool for ensuring continuous confidence in laboratory results.
