Biomarker Profiling for Pyridoxine Dependent Epilepsy in Dried Blood Spots by HILIC-ESI-MS
Table 3
Results of bench top, freeze thaw, autosampler, and long term stability for alpha-amino adipic semialdehyde/piperidine-6-carboxylic acid and pipecolic acid.
Stability expressed as “mean back calculated concentration” (g/mL)± SD,
( change)
Bench top stability (room temperature, 7 hours)
Time point
LQC
HQC
AASA/P6C
Pipecolic acid
AASA/P6C
Pipecolic acid
0 hr
0.44±0.01 (0.00)
0.44±0.01 (0.00)
7.45±0.10 (0.00)
7.54±0.05 (0.00)
0.5 hr
0.44±0.01 (0.00)
0.43±0.00 (0.00)
7.21±0.31 (0.00)
7.49±0.14 (0.00)
1 hr
0.44±0.01 (0.00)
0.43±0.00 (0.00)
7.16±0.21 (0.00)
7.15±0.21 (-5.21)
1.5 hr
0.38±0.02 (-12.44)
0.38±0.01 (-10.73)
6.40±0.02 (-15.00)
6.39±0.21 (-16.13)
2 hr
0.26±0.02 (-39.40)
0.31±0.02 (-29.11)
5.80±0.20 (-22.20)
5.91±0.16 (-21.19)
4 hr
0.10±0.01 (-75.91)
020±0.02 (-53.33)
4.36±0.55 (-41.43)
4.04±1.29 (-46.17)
7 hr
0.06±0.01 (-84.20)
0.07±0.008 (-83.30)
2.91±0.94 (-60.00)
3.79±0.15 (-49.37)
p value
<0.05
<0.05
<0.05
<0.05
Freeze thaw stability (three freeze thaw cycles)
0 cycle
0.44±0.01 (0.00)
0.44±0.01 (0.00)
7.45±0.11 (0.00)
7.50±0.05 (0.00)
3 cycles
0.41±0.02 (-6.31)
0.41±0.02 (-7.15)
7.27±0.38 (-2.45)
7.46±0.06 (-0.53)
p value
0.11
0.08
0.36
0.36
Autosampler stability (4°C, 48 hours)
0 hr
0.45±0.01 (0.00)
0.44±0.01 (0.00)
7.75±0.10 (0.00)
7.50±0.05 (0.00)
6 hr
0.46±0.01 (0.59)
0.45±0.01 (0.52)
7.74±0.11 (-0.14)
7.41±0.14 (-1.15)
12 hr
0.44±0.01 (-3.39)
0.43±0.01 (-3.61)
7.74±0.14 (-0.16)
7.33±0.21 (-2.31)
24 hr
0.42±0.01 (-6.65)
0.42±0.01 (-5.24)
7.71±0.13 (-0.50)
7.28±0.17 (-3.01)
48 hr
0.42±0.03 (-8.35)
0.48±0.03 (-9.23)
7.65±0.14 (-1.23)
7.25±0.16 (-3.30)
p value
0.05
0.04
0.68
0.06
Long term stability (-80°C, 360 days)
0 day
0.45±0.01 (0.00)
0.44±0.01 (0.00)
8.47±0.20 (0.00)
7.18±0.23 (0.00)
7 days
0.46±0.02 (1.13)
0.44±0.02 (0.28)
7.95±0.49 (-6.16)
6.80±0.42 (-5.30)
15 days
0.46±0.03 (2.10)
0.45±0.02 (1.57)
7.94±0.10 (-6.22)
6.73±0.12 (-6.21)
30 days
0.43±0.02 (-6.24)
0.42±0.02 (-6.14)
7.63±0.06 (-9.96)
6.40±0.08 (-10.81)
60 days
0.41±0.01 (-9.89)
0.39±0.02 (-10.95)
7.82±0.34 (-7.69)
6.54±0.30 (-8.91)
90 days
0.41±0.02 (-9.70)
0.42±0.02 (-5.41)
7.86±0.15 (-7.22)
6.72±0.18 (-6.34)
180 days
0.42±0.02 (-7.76)
0.42±0.02 (-5.75)
7.91±0.14 (-6.61)
6.63±0.06 (-7.50)
360 days
0.42±0.00 (-6.96)
0.42±0.00 (-4.05)
7.90±0.12 (-6.77)
6.5±0.11 (-8.43)
p value
<0.01
0.08
0.02
<0.05
Values expressed as mean (standard deviation); statistical treatment performed using repeated measures ANOVA (p value less than 0.05 was considered significant); statistical treatment performed using paired t-test and a p value less than 0.05 which was considered significant. AASA: alpha-amino adipic semialdehyde; P6C: piperidine-6-carboxylic acid.
