Acceptability of plasma ammonia results when samples are not transported and processed under ideal conditions.
Author(s): Bowron A, Osgood V
Publication: Ann Clin Biochem, 2024, Vol. , Page 45632241232931
PubMed ID: 38298138 PubMed Review Paper? No
Purpose of Paper
This paper compared plasma ammonia levels in blood that was stored at room temperature for up to 2 h prior to centrifugation with levels in matched specimens that were stored on ice for 15 min prior to centrifugation.
Conclusion of Paper
Plasma ammonia levels were significantly higher in the specimens stored at room temperature for <15 min than in matched specimens that were stored on ice for 15 min prior to centrifugation and analysis. Ammonia levels increased linearly with storage of blood at room temperature, reaching 30±8.4 μmol/L after 120 min. Despite the large increase, levels remained below the reference limit of 50 μmol/L, leading the authors to conclude that ammonia may be analyzed in plasma isolated from blood specimens that are stored for up to 2 h at room temperature.
Studies
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Study Purpose
This study compared ammonia levels in plasma isolated from blood that was stored at room temperature for up to 2 h with levels in matched specimens from blood stored on ice for 15 min. Blood was collected from 11 healthy adult volunteers into syringes and then transferred into 14 K2EDTA Microvette tubes. One Microvette tube from each volunteer was immediately placed on ice for 15 min, whereas the remaining Microvettes were stored at room temperature. One of the tubes stored at room temperature from each volunteer was analyzed within 15 min (baseline), and subsequently an additional tube was analyzed every 10 min for 2 h. Plasma was isolated by centrifugation at 2000 g for 5 min at 4°C. Ammonia was immediately analyzed in plasma using a Roche c702 analyzer.
Summary of Findings:
Plasma ammonia levels were significantly higher in the specimens stored at room temperature for <15 min than in matched specimens that were stored on ice for 15 min prior to centrifugation and analysis (19±6.6 μmol/L versus 18±6.6 μmol/L, P=0.02). Ammonia levels increased linearly with storage of blood at room temperature (R2 = 0.9896, P<0.001), reaching 30±8.4 μmol/L after an additional 120 min. Importantly, despite the large increase, levels in all specimens remained below the reference limit of 50 μmol/L. The authors concluded that ammonia may be analyzed in plasma from blood specimens that are stored for up to 2 h at room temperature.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Small molecule Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Aliquots and Components Centrifugation Centrifugation delays investigated
Storage Time at room temperature <15 min
Additional 10 min
Additional 20 min
Additional 30 min
Additional 40 min
Additional 50 min
Additional 60 min
Additional 70 min
Additional 80 min
Additional 90 min
Additional 100 min
Additional 110 min
Additional 120 min
Storage Storage temperature On ice
At room temperature