Creatine-kinase MB mass: age and sex-associated reference limits in two different platforms that use the same method

Area of Science:

• Clinical Chemistry
• Biomarker Analysis
• Cardiovascular Diagnostics

Background:

• Troponins are preferred for myocardial necrosis detection per NACB guidelines.
• Creatine kinase-MB (CK-MB) mass remains a viable alternative biomarker when troponin assays are unavailable.
• Establishing reliable gender-specific reference ranges for CK-MB mass is crucial for accurate clinical interpretation.

Purpose of the Study:

• To compare the reliability of two analytical platforms in determining gender-specific 99th percentile values for CK-MB mass.
• To evaluate the impact of gender on CK-MB mass levels in healthy individuals.
• To assess age-related trends in CK-MB mass.

Main Methods:

• Serum samples from healthy individuals were analyzed in two laboratories using Beckman Coulter Access((R)) CKMB methods on UniCel DxI 800 and Access((R)) 2 analyzers.
• CK-MB mass was measured in micrograms per liter (microg/L).
• Plasma samples were also evaluated in one laboratory to compare with serum values.

Main Results:

• Both analytical platforms demonstrated comparable precision, with total imprecision (CV%) ranging from 5.02% to 9.05%.
• A statistically significant gender difference was observed, with higher CK-MB mass values in men (99th percentile: 7.64 microg/L) compared to women (5.19 microg/L).
• Lower median CK-MB mass values were found in younger subjects (18-28 years) compared to older age groups, a trend consistent in both serum and plasma samples.

Conclusions:

• The two analytical platforms provide comparable results for CK-MB mass measurement.
• Significantly higher CK-MB mass values in males compared to females are a critical consideration for patient classification in suspected myocardial necrosis.
• Current commercially available assays often lack this essential gender-specific information, highlighting a gap in diagnostic practice.