Do different assays for human acylated ghrelin concentrations provide comparable results?

Area of Science:

• Biochemistry
• Analytical Chemistry

Background:

• Human ghrelin blood concentrations vary significantly across studies.
• Discrepancies may stem from patient factors, sample processing, analytical methods, and assay manufacturers.
• Limited data exist on the comparability and external validity of ghrelin assays.

Purpose of the Study:

• To compare acylated ghrelin concentrations measured by ELISA and Luminex technology.
• To assess the agreement and reliability of these two common analytical methods for ghrelin measurement.

Main Methods:

• Analyzed 256 human plasma samples for acylated ghrelin.
• Utilized a commercially available enzyme-linked immunoassay (ELISA).
• Employed a multiplex analysis kit with Luminex® technology.

Main Results:

• Both ELISA and Luminex yielded ghrelin concentrations within a similar range.
• ELISA measurements were systematically higher (median 1.4-fold).
• High correlation (Pearson's r=0.753, p<0.01) and good agreement observed via Bland-Altman plots.

Conclusions:

• The two investigated techniques (ELISA and Luminex) demonstrate acceptable agreement for ghrelin measurement.
• The concordance suggests good external consistency and reliability for both analytical methods.
• This study provides a cross-validation for both assays in the absence of a definitive gold standard.