Roche v-TAC

Software application to calculate arterial blood gas values from venous blood

IVD For in vitro diagnostic use.
Icon blood drops

Contact Roche

Contact a Roche representative. Do you have questions about our products or services? We're here to help! Contact us today.

Form Successfully Submitted!
Thank you for your submission!
Laptop screen

navify® Marketplace

Find the digital products and services you need

The new alternative to arterial sampling for blood gas measurement


Arterial blood gas is the gold standard for acid-base and blood gas testing in critical care. However, arterial punctures are complex, painful for the patient and come with a risk of side effects such as haematoma and infections.1,2

Over the recent years there has been an increasing trend towards the use of venous blood, as it is more easily accessible and sample collection is less painful for the patient.6 While pH is largely similar between venous and arterial sampling, the venous pCOand pO2 are different and therefore with limitations for what clinical applications venous blood gas can be used for.6

Roche v-TAC software helps to overcome these limitations.


Arterial blood gas values from a venous blood sample


Roche v-TAC software calculates arterial blood gas (ABG) values from venous peripheral blood gas measurement, combined with arterial oxygen saturation (SpO2), measured by a pulse oximeter.

The precision of the v-TAC calculated values is comparable to that of repeated ABG values for blood gas parameters, including pH, pCO2 and pO2 (up to 10 kPa).5

Roche v-TAC may contribute to clinical, workflow and patient benefits

Icon benefit 1
Improve patient screening in the emergency department

When screening patients, v-TAC reduces the need for separate arterial punctures, as robust arterial blood gas values can be calculated from venous blood.6,7

Icon benefit 2
Gain easier access to arterial blood gas values

With v-TAC, arterial blood gas testing can be done by other staff groups, which improves efficiency and reduces the workload of doctors and specialty-trained staff.6,7

Icon benefit 3
Improve patient experience

Arterial punctures can be painful and with a risk of side effects. The use of venous blood will improve the patient experience and reduce the risk of infections and complications such as hematoma.6,7

How does it work? 


It is very simple to operate Roche v-TAC in daily clinical practice. The software can be used with the cobas b 123 POC system (configurations 3 and 4) and cobas b 221 system from Roche. Additionally, it can work seamlessly with blood gas analyzers from other leading manufacturers.

After implementation, the operational workflow is as follows:

  1. Collect the venous blood sample for blood gas analysis and the corresponding SpO2
  2. Select v-TAC on the blood gas analyser to activate conversion to arterial values and enter the SpO2 value
  3. The v-TAC software calculates the arterial blood gas values which instantly become available to the clinician


Scientific background

The v-TAC Software is based on an advanced algorithm and mathematical models of acid-base and blood chemistry by Rees & Andreassen.8

Watch the v-TAC scientific explanatory video and learn how the v-TAC software calculates arterial blood gas values from peripheral venous blood gas measurements, combined with pulse oximetry measurement of arterial oxygen saturation.

Register now


to be contacted or kept informed about v-TAC.

Form Successfully Submitted!
Thank you for your submission!



HCO3: bicarbonate; kPa: kilopascal; pH: power of hydrogen; pCO2: partial pressure of carbon dioxide; pO2: partial pressure of oxygen; POC: point of care




  1. Word Health Organisation (2010). Article available from [Accessed May 2020]
  2. Hambsch et al. (2015). Clin Transl Sci 8, 857–870
  3. McKeever et al. (2016). Thorax 71, 210-215
  4. Byrne et al. (2014). Respirology 19, 168-175
  5. Toftegaard et al. (2009). Emerg Med J 26, 268-272
  6. Ekström et al. (2019). PLoS ONE 14(4):e0215413
  7. Kamperidis et al. (2018). Thorax 73:A250
  8. Rees SE et al. (2006). Comput Meth Prog Bio 81(1): 18-25.


Ordering Information

Technical Documents

Access Material Data Sheets, Certificates of Analysis, and other product documentation.

After clicking below, you will be redirected to eLabDoc, where you can choose your local country.
error errorMessage
Sorry, we couldn't find the content you are looking for
Please try again later