Determination of reference intervals for serum complement C3 and C4 levels in Chinese Han ethnic males.
BACKGROUND
Clinical laboratory reference intervals (RIs) for serum complement C3 and C4 levels have been established in many countries but there is a lack of published data regarding normal RIs in Chinese population. We attempted to establish RIs for serum complement C3 and C4 levels in Chinese Han ethnic males.


METHODS
A total of 1,234 healthy male subjects, aged 20 - 69 years, were collected from the Fangchenggang Area Male Health and Examination Survey (FAMHES). Serum complement C3 and C4 levels were measured by immunoturbidimetry. The two-sided 95-percentile RIs were calculated using parametric statistical methods.


RESULTS
Serum C3 values showed normal distribution and C4 were log-normal distributed. The two-sided 95% RIs (mean +/- 2 SD) for serum C3 and C4 were 0.656 - 1.52 g/L and 0.181 - 0.561 g/L, respectively. Body Mass Index (BMI) had a significant positive association with C3 (r = 0.342) and C4 (r = 0.258), and age had a significant positive association with C4 (r = 0.117). No significant difference was found either between smoking groups or drinking groups. A significant increase with BMI was found both for C3 (p < 0.001) and C4 (p < 0.001). BMI-specific RIs were also calculated.


CONCLUSIONS
The RIs for serum C3 and C4 show a slight deviation compared to previously reported reference levels. BMI-specific reference values should be implemented in clinical laboratories.
Xue
X
Qin
Yu
Y
Lu
Xiaoli
X
Yang
Qiliu
Q
Peng
Jian
J
Wang
Cuiju
C
Mo
Junrong
J
Wu
Jingzhe
J
Sui
Yanqiong
Y
Liu
Xiuli
X
Huang
Limin
L
Zhai
Shi
S
Yang
Ruolin
R
Li
Shan
S
Li
Xiaobo
X
Yang
Yong
Y
Gao
Zengnan
Z
Mo
D000328:Adult; D000368:Aged; D044466:Asian People / Q000208:ethnology; D015992:Body Mass Index; D002681:China / Q000208:ethnology; D003176:Complement C3 / Q000032:analysis* / Q000096:biosynthesis; D003181:Complement C4 / Q000032:analysis* / Q000096:biosynthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods / Q000592:standards; D012016:Reference Values; D055815:Young Adult
D003176:Complement C3; D003181:Complement C4