Reducing hemolysis in blood samples

Vigorous mixing can lead to a hemolyzed blood gas sample

During the preanalytical phase of blood gas analysis, hemolysis in blood samples can occur if you mix too vigorously. [1]

An example of a hemolyzed blood sample:


Hemolysis in blood samples can occur if you mix too vigorously.



Figure 1, Degree of hemolysis. Modified illustration from Wennecke. Useful tips to avoid preanalytical errors in blood gas testing: electrolytes. 2003 [1]


Vigorous mixing leads to hemolysis in blood gas samples. In a hemolyzed sample erythrocytes rupture and components from inside the cell(s) are released into the plasma. One of these components is potassium (K⁺). [1]

Outcome of hemolysis in blood samples

Hemolysis in blood gas samples leads to erroneous increased potassium values and to other inaccurate values, such as a decrease of pH, pCO₂ and pO₂. [2]

Reduce the risk of hemolysis in blood gas samples

Manual mixing:

Illustration of the mixing process



Figure 2, Mixing of the arterial blood sample [6]


The suggested technique for mixing involves a repeated and gentle inversion of the syringe while rolling it between your palms. [2]

However, you can also use the automatic mixing feature in your blood gas analyzer to obtain a homogenous sample while minimizing the risk of hemolysis from occurring. [3]

Minimize hemolysis in blood samples with automatic mixing

You need to mix a sample sufficiently in order to obtain a homogeneous sample to get accurate results.  However, the technique of manual mixing is applied inconsistently. [4]


Your solution to reducing hemolysis in blood samples lies in automatic mixing.

At Radiometer, we designed the safePICO blood gas syringe to help you adequately mix your sample. The syringe is designed to help reduce the risk of hemolysis in blood samples.

The safePICO syringe


Prior to analysis, sufficient mixing is crucial to obtain a homogeneous sample. The safePICO syringe and automatic mixing on a blood gas analyzer helps you produce a homogeneous sample, while reducing the risk of hemolysis from occurring. [3]

The safePICO syringe helps you reduce the risk of other preanalytical errors. In addition to hemolysis, examples of such errors are clots or an air bubble in the sample, needlestick injuries or patient-sample mix-up.



1. Wennecke G. Useful tips to avoid preanalytical errors in blood gas testing: electrolytes. Oct 2003.
2. Higgins C. Useful tips to avoid preanalytical errors in blood gas testing: pH, pCO₂, and pO₂. Apr 2016.
3. Wennecke G. Bulletin no. 32: Automatic mixing with 1st automatic: Comparison studies. 2005.
4.  Grenache D et al. Integrated and automatic mixing of whole blood: An evaluation of a novel blood gas analyzer. Science Direct 2006; 375, 1-2; 153 – 157
5. Benoit M et al. Evaluation and advantages of an automatic magnetic mixing of syringes integrated with a whole blood gas analyzer. Scandinavian Journal of Clinical & Laboratory Investigation 2009; 69, 5: 628-32.
6. Dukic L et al. Blood gas testing and related measurements: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Biochemia Medica 2016; 26, 3: 318-36.

Cookies are used on this website

Use of cookies
Forgot password
User not found
Radiometer Employee? Enter network username to reset password
We have sent en e-mail to reset your password
Reset your password
Password changed
Password change required.
Please change your password to continue using MyRadiometer.
Password changed