Table 1.

Diagnosis of cystinosis by measuring cystine levels.

Normal	≤0.2 nmol hemicystine/mg protein
Nephropathic cystinosis	5.0–23.0 nmol hemicystine/mg protein
Non-nephropathic cystinosis	1.0–3.0 nmol hemicystine/mg protein
Heterozygous carrier	≤1.0 nmol hemicystine/mg protein
Target levels for treated nephropathic cystinosis	<0.5–1.0 nmol hemicystin/mg protein