High-Sensitivity and Conventional Cardiac Troponin-I Assays in AL Amyloidosis

Area of Science:

• Cardiology
• Biomarker Research
• Hematology

Background:

• Cardiac troponin-I (cTnI) is vital for prognostication in AL amyloidosis.
• High-sensitivity cTnI (HS-cTnI) assays are increasingly used, but their concordance with conventional assays and utility in staging are unclear.

Purpose of the Study:

• To compare cTnI and HS-cTnI assay results in AL amyloidosis patients.
• To evaluate the impact of HS-cTnI on cardiac biomarker staging.

Main Methods:

• Seventy-eight AL amyloidosis patients were prospectively evaluated.
• cTnI and HS-cTnI levels were measured using Abbott Architect and Alinity assays, respectively.
• Deming regression and Bland-Altman analyses assessed assay concordance and bias.

Main Results:

• Median HS-cTnI concentrations were lower than cTnI (7.0 vs 13.0 ng/L).
• Bland-Altman analysis revealed a -49.8% mean difference (negative bias) for HS-cTnI, particularly at concentrations below 50 ng/L.
• HS-cTnI assay use led to downgraded cardiac biomarker staging in 4 patients.

Conclusions:

• While overall agreement exists, HS-cTnI assays exhibit a negative bias at low concentrations.
• Applying conventional cTnI thresholds to HS-cTnI data suggests a trend toward downgraded staging.
• The prognostic value of HS-cTnI in AL amyloidosis biomarker staging requires further investigation.