Multi-Instrument Method Comparison

The Multi-Instrument Method Comparison (MIMC) module evaluates whether multiple analyzers measuring the same analyte produce results that are sufficiently interchangeable for clinical use. Rather than comparing two methods as in a traditional method comparison, MIMC simultaneously assesses 2–30 instruments against a common reference — the target — to determine if each instrument's results fall within allowable error limits across the reportable range.

Results are evaluated using the Error Index, which normalizes each instrument's observed deviation from the target by the Total Allowable Error (TEa). An Error Index magnitude at or below 1.0 indicates that the instrument's bias relative to the target is clinically acceptable. This framework makes it straightforward to identify instruments that systematically disagree with the rest of the fleet, even when concentrations vary across specimens.

Same analyte, all instruments. This module is designed for comparing the same measurand across instruments of the same (or equivalent) analytical type. Selecting instruments configured for different analytes — for example, one instrument set up for serum chloride and another for serum glucose — is not appropriate and will produce meaningless results. All instruments included in the study must be capable of measuring the same analyte, and that analyte must be configured in Lab Settings for each instrument.

When to Use This Module

Multi-instrument comparisons are required whenever a laboratory operates more than one analyzer for the same analyte and needs to confirm that results are interchangeable across instruments:

Multi-instrument laboratories — When two or more analyzers are used interchangeably for the same test, the laboratory must demonstrate that patients receive equivalent results regardless of which instrument processes their specimen.
New instrument added to an existing fleet — When a new analyzer is installed alongside existing instruments that are already in routine use, a MIMC study verifies that the new instrument produces results consistent with the established fleet.
Satellite or point-of-care locations — When the same test is run on analyzers at multiple physical sites (e.g., main lab, satellite lab, emergency department), inter-instrument agreement must be verified to ensure result interchangeability across locations.
After major maintenance or recalibration — Significant corrective maintenance, replacement of major components, or recalibration can shift an instrument's results. A MIMC study confirms that the serviced instrument remains in agreement with the fleet.
Accreditation requirements — CAP and CLIA require laboratories with multiple instruments performing the same test to demonstrate inter-instrument comparability and to document the results in method verification records.