Healthy ranges of serum alanine aminotransferase levels in Iranian blood donors

Table 1 Characteristics of 1939 Blood Donors

Factor	Mean	SE
Age (yr)	37.4	0.26
Weight (kg)	79	0.3
Height (cm)	169.96	0.19
BMI (kg/cm2)	27.35	0.09
ALT (U/L)	19.87	0.27

Abbreviations: SE: Standard error of the mean.

Table 2 Correlation of serum ALT with quantitative clinical factors

Factor	Number	Pearson correlation	P value
BMI	1939	0.125	< 0.001
Weight	1939	0.17	< 0.001
Height	1939	0.096	< 0.001
Age	1939	0.027	0.23

Table 3 Serum ALT according to sex, and BMI (lower or higher than 25)

Variable	Count	Mean	SD	P Value
Female	488	16.4	8.8	< 0.001
Male	1451	21	12.3
All subjects with BMI < 25	563	17.9	10.4	< 0.001
All subjects with BMI ≥ 25	1376	20.7	12.1
Men with BMI < 25	391	19.1	10.8	< 0.001
Men with BMI ≥ 25	1060	21.7	12.8
Women with BMI < 25	172	15.2	8.8	0.025
Women with BMI ≥ 25	316	17	8.7

Abbreviation: SD: Standard deviation.

Table 4 Prevalence among blood donors with normal and abnormal ALT according to the six definitions

Subjects	Method 1:	Method 2:	Method 3:	Method 4: 95th	Method 5: 95th	Method 6: 95th
	95th percentile	95th percentile	40 IU/L for	percentile of	percentile of	percentile of ALT
	of ALT distribution	of ALT distribution	both male	ALT distribution	ALT distribution	distribution stratified
	without stratification	stratified according	and female	stratified according	stratified according	according to BMI
		to sex		to BMI (< 27.1)	to BMI (< 25)	(< 25) and sex
Males	1451	1451	1451	1451	1451	1451
Threshold	40	45	40	39 for BMI ≥ 27.1	39 for BMI < 25	40 for BMI < 25
				41/721	20/391	16/391
				45 for BMI > 27.1	43 for BMI ≥ 25	46 for BMI ≥ 25
				40/730	65/1060	48/1060
Normal (%)	1363 (94%)	1378 (95%)	1363 (94%)	1370 (94.5%)	1366 (94.1%)	1387 (95.6%)
Abnormal (%)	88 (6%)	73 (5%)	88 (6%)	81 (5.5%)	85 (5.9%)	64 (4.4%)
Females	488	488	488	488	488	488
Threshold	40	34	40	39 for BMI ≥ 27.1	39 for BMI < 25	34 for BMI < 25
				6/249	4/172	8/172
				45 for BMI > 27.1	43 for BMI ≥ 25	34 for BMI ≥ 25
				2/239	2/316	15/316
Normal (%)	481 (98.6%)	464 (95%)	481 (98.6%)	480 (98.4%)	482 (98.8%)	465 (95.3%)
Abnormal (%)	7 (1.4%)	24 (5%)	7 (1.4%)	8 (1. 6%)	6 (1.2%)	23 (4.7%)
All donors	1939	1939	1939	1939	1939	1939
Threshold	40	45 for female	40	39 for BMI ≥ 27.1	39 for BMI < 25	Male: 40 for BMI < 25
		34 for male		45 for BMI > 27.1	43 for BMI ≥ 25	46 for BMI ≥ 25
						Female: 34 for BMI < 25
						34 for BMI ≥ 25