Determination of reference intervals for serum complement C3 and C4 levels in Chinese Han ethnic males

Area of Science:

• Clinical Chemistry
• Immunology
• Population Health

Background:

• Reference intervals (RIs) for serum complement C3 and C4 are crucial for clinical diagnostics.
• Existing RIs lack specific data for the Chinese Han ethnic male population.
• This study addresses the need for establishing local RIs.

Purpose of the Study:

• To establish normal reference intervals (RIs) for serum complement C3 and C4 levels in Chinese Han ethnic males.
• To investigate the association of age, Body Mass Index (BMI), smoking, and drinking habits with these complement levels.
• To provide data for accurate clinical laboratory interpretation in this demographic.

Main Methods:

• Utilized data from 1,234 healthy Chinese males aged 20-69 years (Fangchenggang Area Male Health and Examination Survey - FAMHES).
• Measured serum complement C3 and C4 levels using immunoturbidimetry.
• Calculated two-sided 95-percentile RIs using parametric statistical methods.

Main Results:

• Established 95% RIs for serum C3 as 0.656 - 1.52 g/L and for C4 as 0.181 - 0.561 g/L.
• Found significant positive associations between Body Mass Index (BMI) and both C3 (r=0.342) and C4 (r=0.258).
• Observed a significant positive association between age and C4 (r=0.117); no significant differences were noted for smoking or drinking status.

Conclusions:

• The established RIs for serum C3 and C4 show slight deviations from previously reported values.
• Body Mass Index (BMI) significantly influences serum C3 and C4 levels.
• Implementation of BMI-specific reference values is recommended for clinical laboratories serving this population.