RNA has transformed the way we study biology.
Unlike DNA, which provides a relatively static blueprint of an organism, RNA reveals which genes are actively being expressed at a particular moment. Measuring RNA therefore allows researchers to investigate how cells respond to disease, infection, drugs, environmental stimuli and many other biological processes.
However, there is one major challenge.
RNA is remarkably unstable.
The moment blood is collected, the molecular profile inside the sample begins to change. Genes continue to be switched on and off, while enzymes naturally present within blood rapidly begin degrading RNA. Unless these processes are stopped immediately, the RNA extracted from the sample may no longer accurately represent the biological state of the patient at the time of collection.
This is why preserving RNA begins long before the RNA extraction kit is opened.
It begins at the point of blood collection.
Why RNA degrades so quickly
One reason RNA is more difficult to work with than DNA is that it is highly susceptible to degradation.
Cells contain enzymes called ribonucleases, commonly known as RNases, whose role is to break down RNA molecules once they have served their purpose. RNases are extremely stable enzymes and are found almost everywhere. They are present within blood cells, on laboratory surfaces, on skin and even in tiny amounts of environmental contamination.
Once blood leaves the body, these enzymes continue to function.
At the same time, blood cells remain metabolically active for a period after collection. Gene expression does not stop immediately, meaning the RNA profile within the sample continues to change.
As time passes, the sample becomes progressively less representative of the patient's original biological condition.
For studies investigating gene expression, these changes can introduce significant experimental variation.
The importance of immediate RNA stabilisation
The ideal blood sample for transcriptomic analysis is one in which gene expression has been preserved exactly as it existed inside the patient.
Achieving this requires two things to happen as quickly as possible.
First, blood cells must be lysed so that their RNA is released.
Second, RNases must be inactivated before they have an opportunity to degrade the RNA.
Only then can the original gene expression profile be preserved for downstream molecular analysis.
This is precisely the problem that Tempus™ Blood RNA Tubes were designed to solve.
How Tempus™ Blood RNA Tubes work
Unlike a conventional blood collection tube, a Tempus™ Blood RNA Tube already contains approximately 6 mL of RNA stabilising reagent before blood is collected. The tube is calibrated to collect approximately 3 mL of whole blood.
Once the correct volume of blood enters the tube and is mixed immediately, the stabilising reagent rapidly lyses the blood cells.
Cell lysis releases intracellular RNA into the solution.
At the same time, RNases are inactivated, preventing RNA degradation. The stabilising chemistry also promotes selective precipitation of RNA, preserving the original gene expression profile until RNA extraction is performed.
Rather than allowing biological processes to continue after collection, the tube effectively captures a molecular snapshot of the patient's blood at that precise moment.
Why collecting the correct blood volume matters
It may seem that collecting slightly more or slightly less blood would have little consequence.
In reality, the ratio between blood and stabilising reagent is carefully optimised.
Collecting too little blood means the sample becomes excessively diluted, while overfilling the tube reduces the relative amount of stabilising reagent available.
Either situation may compromise efficient cell lysis or complete RNA stabilisation, potentially affecting RNA yield and quality.
For this reason, Tempus™ Blood RNA Tubes are designed to collect approximately 3 mL of whole blood and should not be overfilled or underfilled.
Why immediate mixing is the most critical step
Perhaps the most important step in the entire collection process occurs only seconds after the blood has been drawn.
The tube must be mixed immediately.
This is not simply to blend the contents.
Immediate vigorous mixing ensures that every portion of the collected blood comes into rapid contact with the stabilising reagent. Uniform exposure allows blood cells to lyse quickly, RNases to be inactivated and RNA stabilisation to begin without delay.
If mixing is delayed, even for a relatively short period, some cells may remain intact while gene expression continues to change. RNases may also begin degrading RNA before the stabilising reagent has fully dispersed throughout the sample.
The consequence is that the RNA extracted later may no longer accurately reflect the patient's biological state.
For this reason, the collection procedure specifies vigorous shaking for approximately 10 to 20 seconds immediately after blood collection, making this the critical step in the workflow.
Why storage conditions remain important
Although RNA is stabilised immediately after collection, proper storage remains essential.
RNA stabilisation prevents rapid degradation, but samples must still be stored under validated conditions to maintain long-term integrity.
Tempus™ Blood RNA Tubes can be stored at room temperature for several days, refrigerated for longer periods or frozen at −80 °C for long-term preservation. Repeated freeze–thaw cycles should be avoided because they may reduce sample quality over time.
Appropriate storage provides flexibility for laboratories transporting samples from collection sites to central testing facilities without compromising RNA quality.
Why sample quality determines data quality
RNA extraction cannot restore RNA that has already degraded.
Regardless of how sophisticated the downstream molecular techniques may be, the quality of the final data depends on the quality of the original specimen.
Poorly stabilised samples may produce reduced RNA yields, lower RNA integrity and altered gene expression profiles. These changes can influence downstream analyses such as reverse transcription quantitative PCR (RT-qPCR), RNA sequencing, transcriptomic profiling and biomarker discovery.
By contrast, properly collected and stabilised samples provide a reliable foundation for accurate and reproducible molecular analysis.
Getting RNA collection right from the start
Modern molecular biology increasingly depends on measuring gene expression rather than simply identifying DNA sequences.
As a result, preserving RNA has become one of the most important aspects of blood sample collection.
Tempus™ Blood RNA Tubes simplify this process by combining blood collection with immediate RNA stabilisation. When the correct blood volume is collected, the tube is mixed immediately and samples are stored under appropriate conditions, researchers can be confident that the extracted RNA closely reflects the patient's biology at the moment the blood was drawn.
In molecular diagnostics and transcriptomic research, high-quality data begin not during RNA extraction, but with the very first seconds after blood collection.
Related posts
What Is Next-Generation Sequencing? NGS vs Sanger Explained
Learn how high-quality RNA samples are used in next-generation sequencing and why RNA integrity is critical for reliable sequencing data: https://adwoabiotech.blogspot.com/2026/06/what-is-next-generation-sequencing-ngs.htmlOxford Nanopore Sequencing: A Different Philosophy of Reading DNA
Discover how nanopore sequencing differs from conventional sequencing technologies and its applications in modern molecular biology: https://adwoabiotech.blogspot.com/2026/06/what-is-oxford-nanopore-sequencing-how.htmlSanger Sequencing Explained: How One Missing Oxygen Changed DNA Sequencing Forever
Explore the chemistry behind chain-terminating nucleotides and how Sanger sequencing revolutionised DNA sequencing: https://adwoabiotech.blogspot.com/2026/06/sanger-sequencing-explained-how-one.html
References
1. Tanner MA, Berk LS, Felten DL, Blidy AD, Bit SL, Ruff DW. Substantial changes in gene expression level due to the storage temperature and storage duration of human whole blood. Clin Lab Haematol 2002; 24:337-341.
2. Rainen L, Oelmuller U, Jurgensen S, Wyrich R, Ballas C, Schram J, et. al. Stabilization of mRNA expression in whole blood samples. Clin Chem 2002; 48:1883-1890.
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