I was recently with my grandmother at the Emergency Department because she had difficulty breathing.

After the clinical examination by a doctor, she received both an artery and a vein puncture.

Why is it necessary to take blood from a vein and an artery? The puncture in the artery looked pretty painful so why isn't the vein puncture sufficient?


Venous punctures are typically done for regular blood work such as getting a CBC (Complete Blood Count) and are often enough for regular access - medications etc. Venous access is also used for things such as PIC lines (IV catheters that run almost all the way to the heart).

Arterial punctures are often done for getting a "blood gas". This is used to measure gas levels in the blood (such as CO2 and O2). Arterial punctures can also be used for establishing an arterial line in a large artery such as the femoral.

To sum things up a bit: although venous punctures are more common and often enough; arterial punctures are often needed for more specific testing.

For additional information, please visit MedScape and LabCE. I hope this information is helpful to you, if you have any additional questions, please let me know.

  • 1
    Thank you @L.B for your answer and for improving my question! Now, everything makes sense! ;-) Becky
    – Becky
    Aug 22 '16 at 14:46
  • @Becky Glad to hear it was helpful to you!
    – L.B.
    Aug 22 '16 at 14:55
  • 2
    @Narusan-in-coma Alright... How can I help?
    – L.B.
    Oct 4 '17 at 15:12
  • 1
    @Narusan-in-coma I would be more available in about 76 minutes...
    – L.B.
    Oct 4 '17 at 15:14
  • 1
    @L.B. I have removed a few comments because they were fairly outdated... And luckily, the site progress is completed!
    – Narusan
    Sep 26 '18 at 15:25

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