The correct guideline for assessing interference testing in clinical chemistry assays is CLSI EP07.

CLSI EP07 – <i"Interference Testing in Clinical Chemistry – provides comprehensive recommendations and procedures for evaluating potential interfering substances in clinical assays. It addresses how to identify, evaluate, and quantify interference, which is critical to ensuring the accuracy and reliability of clinical chemistry test results.

Key points include:
- Defining interfering substances such as hemoglobin, lipids, bilirubin, and other endogenous or exogenous compounds.
- Describing methodologies to detect interference, including spiking studies and comparative analysis.
- Providing criteria for acceptance or rejection of assay performance in the presence of potential interferents.
- Outlining statistical approaches to analyze interference effects.

Other CLSI guidelines mentioned:
- CLSI EP15: Focuses on precision and bias verification of quantitative measurement procedures.
- CLSI EP17: Addresses detection capability (limits of detection and quantitation).
- CLSI EP28: Concerns reference intervals and their establishment.

Thus, for laboratory professionals aiming to assess and validate the impact of possible interferences on clinical chemistry assays, CLSI EP07 is the recommended and authoritative guideline.

Reference: Clinical and Laboratory Standards Institute (CLSI) Document EP07, 3rd Edition: Interference Testing in Clinical Chemistry; Approved Guideline.