Healthy range for serum ALT and the clinical significance of "unhealthy" normal ALT levels in the Korean population.
OBJECTIVE
It remains unclear whether the currently-used normal range for serum alanine aminotransferase (ALT) levels really reflects a healthy liver. The present study was conducted to evaluate the healthy range of serum ALT in the Korean adult population and to determine the clinical significance of unhealthy levels.


METHODS
We reviewed the medical records, including questionnaires and the results of laboratory and radiological tests conducted at the Health Promotion Center at Korea University Anam Hospital between March 2005 and February 2007. The records, written in questionnaire form, included baseline data, such as physical status, social behaviors, medication history, and past and present disease histories.


RESULTS
The mean age of the 7403 enrolled patients was 48 years, and 49.9% of these patients were male. A healthy cohort was selected after excluding patients who showed any abnormalities of the factors that were significantly associated with the serum ALT level upon multivariate regression analysis. The upper limit of the healthy range of the serum ALT level (i.e. 95th percentile) in the healthy population was 31 IU/L for males and 23 IU/L for females. The prevalence of metabolic syndrome and insulin resistance (IR) were significantly higher in patients with an 'unhealthy' normal ALT level than in those with a healthy ALT level.


CONCLUSIONS
In our study, the upper limit of the healthy range of the serum ALT level was 31 IU/L for males and 23 IU/L for females. An unhealthy normal ALT level was associated with a higher prevalence of metabolic syndrome and IR.
Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
Hyun Seok
HS
Kang
Soon Ho
SH
Um
Yeon Seok
YS
Seo
Hyonggin
H
An
Kwang Gyun
KG
Lee
Jong Jin
JJ
Hyun
Eun Sun
ES
Kim
Sung Chul
SC
Park
Bora
B
Keum
Ji Hoon
JH
Kim
Hyung Joon
HJ
Yim
Yoon Tae
YT
Jeen
Hong Sik
HS
Lee
Hoon Jai
HJ
Chun
Chang Duck
CD
Kim
Ho Sang
HS
Ryu
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D044466:Asian People / Q000706:statistics & numerical data; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D004796:Clinical Enzyme Tests / Q000592:standards*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000208:ethnology; D016015:Logistic Models; D008297:Male; D024821:Metabolic Syndrome / Q000175:diagnosis / Q000208:ethnology; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012016:Reference Values; D056910:Republic of Korea; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors
D015415:Biomarkers; D000410:Alanine Transaminase