Bioingeniøren (Nov 2013)
Stability of serum proteins at room temperature
Abstract
Diagnostic laboratories require knowledge of the stability of various sample components to assess sample quality. A significant proportion of patient samples are sent by post. Those samples may have been stored in ambient temperature for several days. Stability data of a compound is usually found in the literature. If not, the laboratory needs to obtain such information by carrying out their own studies, which was the background for this study. Serum samples from 30 blood donors were stored for up to seven days in room temperature. Apo A-1, Apo B, prealbumin, β2 -microglobulin, complement factors C3 and C4, FLC-κ and FLC-λ were analysed after 0, 24, 48, 72, 96, 120, 144 and 168 hours by BN ProSpec system (Siemens Healthcare Diagnostics), with an immuno nephelometric method. Two parameters, CDT % and FLC-κ/ FLC-λ-ratio were calculated. The deviations from initial value were compared with the allowable total error. The average differences from the initial value for all 30 samples, and the 90 % CI, were compared with the allowable systematic error (bias). Apo A-1, Apo B and prealbumin were stable for seven days at room temperature. C3 was stable for one day, while C4 was stable for seven days. FLC-κ and FLC-λ were stable for two days, while FLC-κ/FLC-λ ratio was found to be stable for four days when stored in room temperature. β2 -mikroglobulin and CDT % were stable for three days. These conclusions are based on using Siemens nephelometric analysis system and antibodies for quantification.
