Reducing clotted blood samples in blood gas analysis

Inadequate mixing of a sample can lead to a blood sample clotting

Clot formation in blood gas samples can be a result of errors in the preanalytical phase of arterial blood gas analysis. If the anticoagulant in a blood gas syringe isn’t completely dissolved in the blood sample, blood clots may form in the sample. When your blood sample is clotted, then consider it unsuitable for analysis. [1]

Outcomes of clotted blood samples

Clots in the blood gas sample can lead to two outcomes.

First, blood clots can block the pathway of the blood gas analyzer, leading to analyzer downtime.

Second, the blood gas analyzer may produce inaccurate results. This applies for the clotted blood sample and for succeeding samples until the clot has been removed from the analyzer. [2-3]

Reduce the risk of clots in blood samples with adequate manual mixing

Inadequate mixing increases the risk of clot formation in the sample. Mixing your blood sample adequately after collection reduces the risk of blood clots.

When the sample is free of air bubbles, mix the anticoagulant and blood sample adequately. The heparin in the sample needs to dissolve in the blood to reduce clot formation. The recommended technique suggests rolling the syringe between your palms. Then gently and repeatedly invert it vertically. [3-4]

Your solution to reducing clotted blood samples lies in the mixing ball.

At Radiometer, we designed the safePICO blood gas syringe to help you adequately mix your sample. The syringe reduces the risk of your blood sample clotting. 

The safePICO syringe

After sample collection, the built-in mixing ball in the syringe helps you produce a homogeneous sample without clots.

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



1. Narayanan S. Preanalytical issues related to blood sample mixing., Oct 2005.
2. Higgins C. The use of heparin in preparing samples for blood gas analysis., Apr 2007.
3. 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.
4. CLSI. Blood Gas and pH Analysis and Related Measurements; Approved Guideline—Second Edition. CLSI document C46-A2 [ISBN 1-56238-694-8). Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087 USA, 2009.

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