Table 4. Plasma main group results for total and percent cystatin C.

	Total Cystatin C	Perecent Cystatin C
	Mean (ug/ml) ± S.E.M.	Mean (%)± S.E.M.
ALS (n = 43)	0.818±0.024	1.06×10−3±3.36×10−5
DC (n = 11)	0.861±0.048	1.12×10−3±6.78×10−5
HC (n = 31)	0.705±0.023	0.89×10−3±3.17×10−5
Significance of Model Main Effects (p-values)
Diagnosis	0.001*	<0.001*
Gender	0.457	0.293
Age at Draw	0.004*	0.003*
Pairwise Comparisons by Diagnosis (p-values)
ALS vs. DC	0.442	0.419
ALS vs. HC	0.001*	<0.001*
DC vs. HC	0.004*	0.002*

Both measures of cystatin C differed significantly by age at draw and by diagnostic category. Cystatin C levels were significantly elevated in ALS patients and disease controls relative to healthy controls but there were no differences in cystatin C levels between ALS patients and disease controls. Asterisks indicate statistical significance at p<0.05.