Stability of serum TSH concentration after non refrigerated storage.
BACKGROUND
The ignorance of how sensitive serum samples for defined assays may be, can lead to overprotecting measures. This attitude not only increases cost and labor in everyday routine but may be responsible for not evaluating series of measurements if performed in serum samples not well stored.


METHODS
Thyrotropin (TSH) concentration in serum was tested in three pooled samples drawn from various patients, before and after four days storage at freezing (-15 degrees C), low (4 degrees C), and room temperature (18-22 degrees C). TSH concentration was measured in each part, in 22 replicates using a commercial assay.


RESULTS
The variation of the measured values due to the storage conditions was less than 10%, not exceeding the accepted between assay variation.


CONCLUSIONS
For the estimation of TSH concentration, patient serum samples may be stored up to four days at 4 degrees C or even at room temperature without significant loss of measurement accuracy.
Koliakos
G
G
Department of Biological Chemistry, AHEPA General Hospital, Medical School Aristotele, University of Thessaloniki, Greece.
Gaitatzi
M
M
Grammaticos
P
P
D001669:Biochemical Phenomena; D005615:Freezing; D006801:Humans; D013972:Thyrotropin / Q000097:blood*
D013972:Thyrotropin