Table 3. Results of accuracy, precision and recovery of method validation using quality control samples.

Analytes	QC (ng/mL)	Intra-day (n = 5)		Inter-day (n = 5)		Recovery (%)
		Accuracy (%)	Precision (%)	Accuracy (%)	Precision (%)
Serum
24S-OHC	5	96.0	4.7	97.7	10.4	89.8
	10	95.0	4.1	99.7	4.5	88.1
	100	106.0	0.5	100.9	3.0	85.8
	200	99.1	0.9	100.1	1.2	82.7
25-OHC	0.5	109.7	8.2	93.3	14.7	90.7
	1	98.6	5.5	92.5	7.2	89.7
	10	103.0	0.5	105.1	4.1	87.5
	20	94.9	0.9	97.4	2.2	83.7
27-OHC	5	104.5	8.2	107.3	7.5	85.8
	10	103.8	5.5	107.4	4.2	87.5
	100	99.7	0.5	96.0	1.9	88.7
	200	99.7	0.8	101.1	1.0	84.0
CSF
24S-OHC	0.1	97.1	7.6	96.2	4.5	83.7
	0.5	101.6	5.3	108.1	2.3	95.8
	2	98.7	1.4	98.0	1.8	97.2
	5	99.7	1.6	98.5	0.8	92.6
25-OHC	0.03	112.9	7.3	119.2	4.5	68.4
	0.1	107.8	4.0	109.2	3.9	98.5
	0.5	99.6	1.3	101.0	2.3	99.6
	1	107.5	1.2	110.3	3.2	93.2
27-OHC	0.1	115.8	7.7	108.3	3.5	88.2
	0.5	101.3	1.8	100.8	1.6	105.0
	2	97.1	2.3	94.5	2.4	103.2
	5	99.8	1.2	96.3	2.6	97.3