Long-Term Stability of Hydromorphone in Human Plasma Frozen at −20°C for Three Years Quantified by LC-MS/MS

Table 3

Deviation between the hydromorphone plasma concentrations when re-analyzed in 2019 from thawed samples after more than three years and the first measurements in 2016.

Patient number	Concentration difference (ng/mL)	%RE	n
36	−0.20 ± 0.80	−2.88 ± 13.6	15
39	0.41 ± 0.94	8.35 ± 12.7	14
43	−0.53 ± 0.76	−8.07 ± 13.7	15
Overall	−0.12 ± 0.90	−1.07 ± 14.8	44

%RE: relative deviation.