Temperaturens och tidens inverkan under transport och förvaring av urinodlingsprover

Sammanfattning

Objectives Although urine culture has long been used to diagnose urinary tract infections, it remains susceptible to pre-analytical errors. The primary causes are contamination during sample collection and improper storage and transport conditions. Because urine samples are transported across the Region of Västernorrland throughout the year, maintaining the recommended storage temperature can be challenging. This study aimed to investigate the effects of prolonged improper storage of urine samples and to evaluate how such samples should be handled to minimize diagnostic errors. Materials and Methods Clinical urine samples (n = 30) were each aliquoted into four new test tubes. The test tubes were then stored at four different temperatures (−15 °C, 1 °C, 15 °C, and 22 °C) for 72 hours. Samples were cultured every 24 hours on two defibrinated horse blood agar plates and two Brilliance™ UTI agar plates. Clinically relevant bacteria were identified using Matrix-Assisted Laser Desorption/Ionisation-Time of Flight Mass Spectrometry (MALDI-TOF MS). Results and Conclusions Frozen samples showed a high risk of false negatives results, whereas samples stored at room temperature showed a high risk of false positives results. Storage at 15 °C for 24 hours showed similar performance to storage at 1 °C for 72 hours, with two false negative results. These findings suggest that samples transported above the recommended temperature for a limited period may still be suitable for analysis. Further studies are needed to determine acceptable storage times and temperatures.