Table 4.

Elevated urine creatine levels and their follow-up investigations

Urine creatine reference range per age groups	Number of elevated urine creatine levels in males and females	Elevated urine creatine range (mmol/mol creatinine) (median)
		Follow-up investigations
0–60 months (reference range 14–830 mmol/mol creatinine)	Male	838.0–3915.00 (1082.5)
	N = 29	Normal MRS n = 8
	No confirmatory follow-up investigations n = 9	Normal genetic investigations for CRTR deficiency n = 12
	Female	843.0–2333.0 (1190.0)
	N = 25	Normal MRS n = 6
	No confirmatory follow-up investigations n = 13	Normal genetic investigations for CRTR deficiency n = 12
60–192 months (reference range 16–649 mmol/mol creatinine)	Male	707.0–3518.0* (835)
	N = 7	Normal MRS n = 1
	No confirmatory follow-up investigations n = 3	Normal genetic investigations for CRTR deficiency n = 2
		Diagnosis of CRTR deficiency n = 1
	Female	657.0–8756.0** (885)
	N = 9	Normal MRS n = 1
	No confirmatory follow-up investigations n = 6	Normal genetic investigations for CRTR deficiency n = 2
		Diagnosis of CRTR deficiency n = 1
192–228 months (reference range 19–173 mmol/mol creatinine)	Male	531
	N = 1	Normal genetic investigations for CRTR deficiency n = 1
	Female	Result = 186.0
	N = 1
	No confirmatory follow-up investigations n = 1

*Maximum value is male patient identified with CRTR without therapy

**Maximum value is female patient identified with CRTR with therapy