Effect of heat treatment of potentially infected blood samples on therapeutic drug monitoring of selected drugs.
OBJECTIVE
To investigate the effect of heart treatment on the outcome of drug analysis in whole blood and serum for eight drugs routinely assayed for therapeutic monitoring.


METHODS
All blood and serum samples (n = 373) received at the pharmacy laboratory for therapeutic monitoring of carbamazepine, digoxin, gentamicin, kanamycin, phenobarbital, phenytoin, theophylline, and valproic acid were heated at 60 degrees C for 30 minutes. Serum was subsequently assayed by fluorescence polarization immunoassay (TDx).


METHODS
The study was conducted at the analytical laboratory of the pharmacy, using standard laboratory procedures.


METHODS
Analyses of heated samples were compared with analyses of untreated samples using a paired Wilcoxon signed-rank test.


RESULTS
Serum concentrations of phenytoin from treated whole blood, and gentamicin in treated serum, were significantly lower than in untreated samples. These differences, however, were small, clinically irrelevant, and lie within assay variation intervals. Heat treatment did not influence the outcome of analyses for carbamazepine, digoxin, kanamycin, phenobarbital, theophylline, and valproic acid.


CONCLUSIONS
Heat treatment of whole blood and serum samples of the investigated drugs does not influence the outcome of drug analysis, although drug instability cannot be fully excluded. Heat treatment can protect laboratory technicians from HIV infection without influencing therapeutic monitoring of these drugs.
Burger
D M
DM
Department of Pharmacy, Slotevaart Hospital, Amsterdam, The Netherlands.
van Dijk
E A
EA
van Gijn
R
R
Beijnen
J H
JH
D001790:Blood Physiological Phenomena; D003428:Cross Infection / Q000517:prevention & control; D016903:Drug Monitoring; D004355:Drug Stability; D016231:Fluorescence Polarization Immunoassay; D015658:HIV Infections / Q000517:prevention & control; D006358:Hot Temperature; D006801:Humans; D004364:Pharmaceutical Preparations / Q000032:analysis*; D013048:Specimen Handling
D004364:Pharmaceutical Preparations