{"id":"pco2-venous","name":"Venous pCO2","shortName":"Venous pCO2","aliases":["pCO2, Venous","PvCO2","pCO2 (VBG)","Carbon Dioxide Partial Pressure, Venous","Venous pCO2","pCO2 venous","PCO2, Venous","pvCO2","VBG pCO2","pCO2 (venous)","Venous carbon dioxide tension","Carbon dioxide tension, venous"],"abbreviations":["PvCO2","pvCO2","vPCO2"],"loinc":[{"code":"2021-4","primary":true},{"code":"97538-3","primary":false},{"code":"19212-0","primary":false}],"specimen":"whole-blood","units":[{"ucum":"mm[Hg]","display":"mmHg"},{"ucum":"kPa","display":"kPa"}],"referenceRanges":[{"population":"Adults","low":38,"high":58,"unit":"mm[Hg]","unitDisplay":"mmHg","note":"Venous interval of 38–58 mmHg (5.1–7.7 kPa) measured in 134 healthy Australian adults on a Radiometer ABL827 analyzer. A study of 182 healthy adults in Pakistan found 35–59 mmHg. The first group's calculated intervals from arterial ranges were 36–49 mmHg for women and 39–52 mmHg for men, and reviews quote about 41–51 mmHg for mixed venous blood. Directly measured venous intervals are wide because venous pCO2 varies with local blood flow. Alberta Precision Laboratories prints a narrower 35–50 mmHg for venous blood. A 2025 review cites a venous pCO2 under 45 mmHg as effectively ruling out a high arterial value, so results in the upper part of this wide range are less reassuring. Labs set their own limits, so use the range printed on your report. Adult values only.","sources":[{"title":"Reference intervals for venous blood gas measurement in adults","url":"https://doi.org/10.1515/cclm-2020-1224","publisher":"Clinical Chemistry and Laboratory Medicine 2021;59(5):947-954","year":2021},{"title":"Reference Intervals for Venous Blood Gas in Healthy Adults: A One-Year Prospective Study","url":"https://doi.org/10.7759/cureus.74223","publisher":"Cureus 2024;16:e74223","year":2024},{"title":"The Role of Venous Blood Gas Analysis in Critical Care: A Narrative Review","url":"https://doi.org/10.3390/medicina61081337","publisher":"Medicina (Kaunas) 2025;61:1337","year":2025},{"title":"Laboratory Bulletin: Changes to Blood Gas Reference Intervals and Critical Values","url":"https://www.albertahealthservices.ca/assets/wf/lab/if-lab-hp-lab-bulletin-changes-to-blood-gas-reference-intervals-and-critical-values.pdf","publisher":"Alberta Precision Laboratories (Alberta Health Services)","year":2021}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"The pressure of carbon dioxide dissolved in blood from a vein. It reflects how well your lungs clear CO2 and runs a few mmHg above the arterial value.","url":"https://bloodtesttracker.com/markers/pco2-venous","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}