Table 4.

Technical and biological reproducibility of amino acid concentrations quantified in red blood cells. Experimental conditions were the same as in Table 1. The technical reproducibility was calculated from 3 sequential UPLC-MS/MS analysis. The biological reproducibility was calculated across 6 biological replicates, each analyzed three times by UPLC-MS/MS.

Amino acid	Technical reproducibility			Biological reproducibility
	pmol/μL	CV %	ST Error	pmol/μL	CV %	ST Error
Histidine	15.6163	9.29	0.8373	15.0506	12.37	0.4654
Asparagine	496.2070	1.97	5.6581	435.5660	16.23	16.6630
Hydroxy-L-Proline	12.4053	8.58	0.6147	12.2486	7.88	0.2275
Taurine	4.6445	9.36	0.3075	6.3641	41.33	0.6791
Arginine	6.3820	7.21	0.2657	8.0786	23.12	0.4530
Aspartic acid	35.3750	1.35	0.2749	69.1045	50.06	8.1540
Serine	29.0133	13.26	2.2219	28.7161	16.49	1.1482
Glycine	36.2560	8.82	1.8465	67.5955	44.36	7.0675
Citrulline	4.5825	9.77	0.3165	5.8364	23.15	0.3900
Glutamic acid	19.3850	3.14	0.3512	25.7587	24.96	1.5593
Alanine	0.4380	2.26	0.0070	0.6801	53.65	0.1100
Proline	16.0703	9.58	0.8888	21.8726	24.59	1.2674
α-amino-n-butyric acid	0.2523	6.94	0.0101	0.2520	25.66	0.0179
γ-Amino-n-butyric acid	0.2015	6.67	0.0095	0.1171	60.27	0.0166
Tyrosine	14.8157	14.35	1.2275	16.5172	18.27	0.7319
Methionine	2.2285	4.09	0.0645	2.8053	28.92	0.2342
Lysine	9.7890	2.53	0.1750	10.4553	44.43	1.6425
Valine	5.9700	10.47	0.4420	9.8059	42.56	1.0435
Tryptophan	2.0190	6.76	0.0788	2.1402	34.73	0.1987
Phenylalanine	1.5917	3.94	0.0362	2.6696	55.86	0.3986
Leucine	4.7270	4.64	0.1550	8.9685	37.47	0.8402
Isoleucine	6.8557	12.92	0.5115	9.7329	33.75	0.8481
Threonine	16.7190	1.02	0.1210	17.3410	9.35	0.3934
Amino adipic acid	0.1633	10.96	0.0103	0.2074	28.72	0.0159
Ornitine	23.6730	3.12	0.5220	36.8569	25.12	3.2740