Biological variation and reference change values of serum Mac-2-binding protein glycosylation isomer (M2BPGi).

BACKGROUND

Limited data are available with regard to biological variations of the Mac-2-binding protein glycosylation isomer (M2BPGi), a liver fibrosis biomarker.

METHODS

Long-term biological variation of M2BPGi was investigated using longitudinally measured M2BPGi test results from healthy Korean adult subjects. One-way analysis of variance (ANOVA) tests were used to calculate the reference change value (RCV) of M2BPGi based on biological variation estimates. Furthermore, asymmetric RCV was calculated according to a recent publication of the European Federation of Clinical Chemistry and Laboratory Medicine Working Group on Biological Variation and Task Group for the Biological Variation Database (EFLM TG-BVD).

RESULTS

A total of 363 test results from 174 Korean subjects undergoing general health checkups were requested from 13 local clinics and hospitals during a 38-month period. The within-subjects biological variation (CV ), between-subject biological variation (CV ), analytical variation (CV ), RCV, and individuality index (II) values for serum M2BPGi were 23.3%, 30.0%, 4.3%, 65.6%, and 0.78, respectively. Asymmetric RCV calculated using formulae by a recent EFLM TG-BVD publication ranged from -41.9 to 72.0%. Desirable analytical performance specifications for M2BPGi derived from biological variation were as follows: imprecision 11.6%, bias 9.6%, and total allowable error 28.7%.

CONCLUSIONS

RCV based on biological estimates may be helpful for evaluating and interpreting serial M2BPGi measurements by physicians and in clinical laboratories.