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Published on: November 2, 2013
Stability of serum TSH concentration after non refrigerated storage
G Koliakos1, M Gaitatzi, P Grammaticos
1Department of Biological Chemistry, AHEPA General Hospital, Medical School Aristotele, University of Thessaloniki, Greece.
Insights
Serum samples for thyroid-stimulating hormone (TSH) testing can be stored for up to four days at room temperature or 4°C. This finding simplifies sample handling and reduces unnecessary protective measures in clinical laboratories.
Area of Science:
- Clinical Chemistry
- Endocrinology
- Laboratory Medicine
Background:
- Serum sample stability is crucial for accurate diagnostic assays.
- Overly cautious storage protocols increase laboratory costs and workload.
- Improper storage can lead to the exclusion of valuable patient data.
Purpose of the Study:
- To determine the stability of thyrotropin (TSH) in serum samples under various storage conditions.
- To assess the impact of short-term storage on TSH measurement accuracy.
- To provide evidence-based guidelines for serum sample handling in clinical practice.
Main Methods:
- Pooled serum samples were subjected to storage at -15°C, 4°C, and room temperature (18-22°C) for four days.
- Thyrotropin (TSH) concentrations were measured using a commercial assay in 22 replicates for each condition.
- Variations in TSH levels were analyzed based on storage duration and temperature.
Main Results:
- Storage of serum samples for up to four days resulted in less than 10% variation in measured TSH values.
- The observed variation did not exceed the acceptable limits for inter-assay variability.
- TSH concentrations remained stable across different storage temperatures, including room temperature.
Conclusions:
- Patient serum samples for TSH estimation can be reliably stored for up to four days at 4°C or room temperature.
- Standardized storage conditions can be relaxed without compromising diagnostic accuracy for TSH.
- These findings support streamlined laboratory workflows and reduced costs associated with serum sample management.
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.
