Why do AdnaTest blood samples need to be processed within 4 hours,2 Dec 2025 16:38
Yet Parsortix ones in 8 or more?
A.I.
The difference in required processing times for AdnaTest (4 hours) and Parsortix (8 hours with standard EDTA tubes) is
due to their distinct mechanisms of action and the specific preservation of target cells and their components (mRNA vs. physical cell integrity).
AdnaTest (4 hours)
Mechanism and Target: The AdnaTest is designed for the detection of specific mRNA biomarkers (e.g., KLK3, PSMA, EGFR) in captured circulating tumor cells (CTCs).
Time Sensitivity: RNA is a highly unstable molecule with a very short half-life and is prone to rapid degradation by circulating RNases and cell lysis outside the body. This degradation starts immediately after the blood is drawn.
Requirement: To ensure the integrity and reliable detection of these specific mRNA transcripts, the sample must be processed quickly (within 4 hours) and typically transported on ice to minimize RNA degradation. Delayed processing can lead to false-negative results or altered gene expression profiles, making the data unreliable for analysis.
Parsortix (8 hours)
Mechanism and Target: The Parsortix system is a size- and deformability-based microfluidic technology that enriches intact CTCs from whole blood. Its primary goal is the physical capture of the cells themselves, which can then be used for various downstream analyses, including cell culture, DNA analysis, or immunofluorescent staining.
Time Sensitivity: While all blood samples degrade over time, the Parsortix method is more robust to the initial post-collection changes compared to the AdnaTest's delicate mRNA target. Studies show that using standard K2EDTA tubes, the cell capture rate remains stable for longer, with processing recommended within 8 hours for optimal results.
Flexibility with Preservatives: The Parsortix system also has the advantage of being compatible with specialized preservative-containing blood collection tubes (e.g., CellSave or Transfix tubes). When these tubes are used, the processing window can be extended significantly, up to 96 hours (4 days) at room temperature, because the fixatives help maintain cell membrane integrity and prevent degradation.
In essence, the AdnaTest's shorter window is due to the extreme fragility of its target analyte (mRNA), while the Parsortix system's reliance on physical cell capture allows for a slightly more forgiving processing timeframe with standard tubes and even longer stability with specialized preservative tubes.
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VERY interesting indeed!