Consistency study of IGF-1 detection by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry...

Insulin-like Growth Factor I (IGF-1) is crucial for growth, metabolism, and cell proliferation. Its detection is significant for diagnosing and monitoring various diseases. Chemiluminescence immunoassay (CLIA) is commonly used for IGF-1 detection but is prone to interference and variability. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) offers higher specificity and sensitivity but is less clinically applied. This study compared the consistency of serum IGF-1 levels detected by MALDI-TOF MS and CLIA.

A total of 660 serum samples from healthy individuals aged 0 to 90 years were included and analyzed using MALDI-TOF MS and CLIA methods. Initially, the MALDI-TOF MS results for the full cohort were assessed for agreement with age- and sex-specific reference intervals provided by the CLIA kit. Subsequently, a subset of 108 participants underwent paired testing under identical conditions to evaluate method comparability. The consistency between the two methods was evaluated using linear regression, the intraclass correlation coefficient (ICC), and Bland-Altman analysis.

In most age groups, the results of IGF-1 concentration measured by MALDI-TOF MS fell within the reference range established by CLIA. A strong correlation (R² = 0.982) was observed between the two methods, with the regression equation defined as IGF-1_CLIA = 0.972 × IGF-1_{MALDI-TOF MS} + 5.041. The correlation coefficients were 0.994 in children and 0.985 in adults (P < 0.001), and ICC values exceeded 0.80, indicating high consistency. Bland-Altman analysis showed a mean difference of -0.25 ng/mL, with 95% limits of agreement ranging from -24.54 to 24.04 ng/mL, which falls within the clinically acceptable range.

MALDI-TOF MS shows good consistency with CLIA in detecting serum IGF-I levels, providing evidence for its clinical application.