Age-Specific Cut-off Values of Amino Acids and Acylcarnitines for Diagnosis of Inborn Errors of Metabolism Using Liquid Chromatography Tandem Mass Spectrometry

Table 1

The cut-off values of the analytes and marker ratios for screening of IEMs.

Suspected disease	Analytes/Marker ratios	Cut-offs; Group A; (mol/L)	Cut-offs; Group B; (mol/L)	Cut-offs; Group C; (mol/L)
PKU	↑ Phe	> 85.45	> 88.12	> 82.08
	↑ Phe/tyr	> 3.47	> 5.11	> 8.03
BHD	↑ Phe/tyr	> 3.47	> 5.11	> 8.03
CIT	↑ Cit	> 17.17	> 35.91	> 39.74
	↑ Cit/Phe	> 0.42	> 0.75	> 0.80
TYR	↑ Tyr	> 199.96	> 128.12	> 136.63
	↑ Tyr/Phe	> 5.90	> 2.50	> 2.56
MSUD	↑ Val	> 188.83	> 187.45	> 210.34
	↑ Xle	> 200.85	> 201.74	> 220.69
	↑ Val/Phe	> 5.37	> 3.35	> 4.05
	↑ Xle/Ala	> 1.37	> 1.44	> 1.23
	↑ Xle/Phe	> 5.62	> 3.37	> 4.14
ARG	↑ Arg	> 21.39	> 74.98	> 95.36
	↑ Arg/Orn	> 0.26	> 1.00	> 1.04
OTC	↓ Cit	< 4.68	< 11.51	< 13.67
	↑ Orn	> 112.77	> 145.61	> 148.49
HCY	↑ Met	> 42.38	> 40.65	> 42.17
	↑ Met/Phe	> 0.74	> 0.77	> 0.78
MMA	↑ C3	> 6.88	> 2.69	> 2.70
	↑ C3/C2	> 0.19	> 0.15	> 0.14
IVA	↑ C5	> 0.55	> 0.26	> 0.29
	↑ C5/C3	> 0.42	> 0.16	> 0.19
GA-II	↑ C4	> 0.63	> 0.33	> 0.38
	↑ C8	> 0.14	> 0.14	> 0.30
	↑ C14	> 0.51	> 0.27	> 0.13
	↑ C16	> 7.23	> 2.47	> 2.20
	↑ C12	> 0.23	> 0.14	> 0.15
GA-I	↑ C5DC	> 0.29	> 0.17	> 0.20
CUD	↓ C0	< 15.60	< 12.34	< 13.38
	↓ C2	< 6.88	< 8.71	< 9.05
CPT-I	↑ C0	> 73.73	> 69.76	> 75.67
	↑ C0/(C16+C18)	> 21.67	> 43.54	> 56.08
	↓ C16	< 0.88	< 0.61	< 0.55
SCAD	↑ C4	> 0.63	> 0.33	> 0.38
	↑ C4/C2	> 0.03	> 0.02	> 0.02
MCAD	↑ C6	> 0.09	> 0.09	> 0.12
	↑ C8	> 0.14	> 0.14	> 0.30
	↑ C10	> 0.18	> 0.23	> 0.58
	↑ C10:1	> 0.11	> 0.16	> 0.21
	↑ C10:2	> 0.02	> 0.08	> 0.08
	↑ C8/C10	> 1.67	> 4.43	> 2.45
	↑ C8/C2	> 0.01	> 0.01	> 0.02
VLCAD	↑ C14:1	> 0.34	> 0.16	> 0.26
	↑ C14:1/C16	> 0.09	> 0.16	> 0.22
	↑ C14	> 0.51	> 0.27	> 0.13
CPT-II	↑ C16	> 7.23	> 2.47	> 2.20
CACT	↑ C18	> 1.69	> 0.91	> 0.88
	↑ C18:1	> 1.98	> 1.57	> 1.67
TFP	↑ C18OH	> 0.05	> 0.01	> 0.01
	↑ C18:1OH	> 0.03	> 0.02	> 0.02

PKU, phenylketonuria; BHD, BH4 deficiency; CIT, citrullinemia; TYR, tyrosinemia; MSUD, maple syrup urine disease; ARG, argininemia; OTC, ornithine transcarbamylase deficiency; HCY, homocystinuria; MMA, methylmalonic acidemia; IVA, isovaleric acidemia; GA-II, glutaric acidemia type II (multiple acyl-CoA dehydrogenase deficiency); GA-I, glutaric acidemia type I; CUD, carnitine uptake defect; CPT-I, carnitine palmitoyltransferase I deficiency; SCAD, short-chain acyl-CoA dehydrogenase deficiency; MCAD, medium-chain acyl-CoA dehydrogenase deficiency; VLCAD, very long-chain acyl-CoA dehydrogenase deficiency; CPT-II, carnitine palmitoyltransferase II deficiency; CACT, carnitine-acylcarnitine translocase deficiency; TFP, trifunctional protein deficiency.