Effect of blood contamination of cerebrospinal fluid on amino acids, biogenic amines, pterins and vitamins

Table 2 Percentage of variation of the different biomarkers measured according to the different volumes of blood spiked into the CSF (expressed as percentage) when compared with the non-spiked CSF samples

Biomarkers (% blood contamination)	A) RBC lysed				B) RBC removed
Biomarkers (% blood contamination)	20%	10%	5%	2.5%	20%	10%	5%	2.5%
Albumin	2724	1372	667	323	2877	1379	669	318
Taurine	393	194	112	48	189	91	45	14
Aspartate	1404	842	401	252	42	25	< 10	< 10
Threonine	70	43	21	14	69	38	14	< 10
Serine	45	18	13	< 10	22	15	< 10	< 10
Glutamate	611	394	205	107	57	27	16	< 10
Glutamine	14	< 10	< 10	< 10	< 10	< 10	< 10	< 10
Glycine	229	114	61	43	114	60	21	< 10
Alanine	174	95	46	23	154	72	30	11
Citrulline	151	56	22	< 10	112	42	20	< 10
Valine	138	79	40	23	161	83	36	13
Methionine	141	78	38	20	151	73	39	11
Isoleucine	125	68	34	19	136	69	29	< 10
Leucine	113	62	27	17	123	65	30	< 10
Tyrosine	84	43	20	11	87	41	19	< 10
Phenylalanine	63	38	18	11	66	39	18	< 10
Ornithine	346	256	154	107	86	41	14	< 10
Lysine	113	66	31	16	100	50	22	< 10
Hystidine	93	44	18	< 10	80	42	18	< 10
Arginine	− 47	− 56	− 51	− 39	51	27	< 10	< 10
5-HIAA	− 42	− 37	− 41	− 44	< 10	< 10	< 10	< 10
HVA	− 22	− 11	< 10	< 10	< 10	< 10	< 10	< 10
Biopterin	< 10	< 10	< 10	< 10	< 10	< 10	< 10	< 10
Neopterin	12	< 10	< 10	< 10	< 10	< 10	< 10	< 10
Thiamine	198	154	175	169	135	68	37	27
5-MTHF	74	52	33	19	< 10	< 10	< 10	< 10
PLP	270	157	102	60	157	80	45	29
Hemoglobin (g/dL)	3.02	1.55	0.76	0.37
TDP (nmol/L)	25	14	11	4.5

Data are expressed as the mean value of the 2 CSF pools from the 2 conditions: A) spiked CSF frozen containing lysed-RBC cells (left columns), and B) spiked CSF with RBC removed by centrifugation prior freezing (right columns). A percentage of variation below 10% (comparing spiked CSF samples to the non-spiked CSF samples) was considered as the cut-off value for a proper interpretation of the results, considering the coefficient of variation for every biomarker measured when procedures were standardized. Haemoglobin and TDP values are expressed in g/dL and nmol/L, respectively since their values in condition B were not detectable. A total of 20 CSF aliquots coming from 50 CSF samples were analysed (Additional file 2: Figure S1)

ISSN: 2045-8118