Taking Blood Samples from a PIVC: Yes or No?

We are often asked if it's okay to take blood samples from a peripheral intravenous catheter (aka PIVC, cannula). In Australia, each state has a different policy, however, most allow blood draws on insertion of the cannula.

The Infusion Nurses Society Standards of Practice 8^th edition (2021, page S129) has the following recommendations, based on evidence:

"Risks associated with sampling from a PIVC include hemolysis of the sample, contamination of the sample from infusing solutions and medications, local complications from excessive catheter movement (e.g., phlebitis, infiltration), and dislodgement from the insertion site.72 (IV)

“Obtaining the sample at the time of insertion may result in hemolysis and spurious laboratory values due to length of tourniquet time. Study protocols have reported stopping infusing solutions for 1 to 2 minutes and wasting 1 to 2 mL of blood. Sampling of blood from indwelling short PIVCs produced results for complete blood counts, blood chemistry, and coagulation studies that are not different from a direct venipuncture. Although most studies show some level of statistical difference when compared to direct venipuncture, these differences were not relevant to clinical decisions. Obtaining blood cultures from short PIVCs at insertion or during the dwell is not recommended. (V)

“Higher hemolysis rates are associated with blood sampling from short PIVCs. One systematic review highlighted many confounding variables without adequate control, including visual or automated hemolysis measurement, use of evacuated tubes vs syringes, and catheter gauge and site. Hemolysis rates of less than 5% may be acceptable in patients requiring frequent blood sampling and/or who have difficult peripheral veins. High rates of hemolysis (e.g., 15%) may be offset by the significantly high rates of parent/patient satisfaction with using the catheter for this purpose. (IV)

“Veins of the antecubital fossa produce the lowest rates of hemolysis. However, short PIVCs inserted for infusion into veins of the antecubital fossa are not recommended due to higher catheter complication rates in areas of joint flexion. (IV)”

Further suggestions recommend that a PIVC protocol for blood sampling should include:

·       strict aseptic technique

·       halt infusion of solution for at least 2 min prior to blood draw

·       use a 20 gauge or larger catheter

·       the quantity of blood to be discarded should be double the dead space

·      using a needleless connector to draw blood from the PIVC, thus reducing the opportunity of a potential needlestick injury

·       use a syringe to aspirate the blood not a vacutainer

·       avoid excessive aspiration force

·       do not under-fill the blood tubes.

Pragmatically, nurses have stated taking blood from a PIVC may occur in an emergency; patients with difficult venepuncture and limited venous access; patients requiring multiple blood draws (troponin, haemoglobin and glucose tolerance testing); patients who are obese, dehydrated or oedematous; and patients on anticoagulation therapy who are at increased risk of bleeding.

Further research is required to investigate if drawing blood from a PIVC is of benefit for specific populations and in other settings besides the emergency department.

Further reading

Ben Shabat I, Ben Shabat MH, Ben Abraham S, et al. Reliability of blood tests taken from the peripheral intravenous catheter. Medicine (Baltimore). Jul 15 2022;101(28):e29268. https://doi.org/10.1097/MD.0000000000029268

Coventry LL, Jacob AM, Davies HT, Stoneman L, Keogh S, Jacob ER. Drawing blood from peripheral intravenous cannula compared with venepuncture: A systematic review and meta-analysis. J Adv Nurs. 2019;75(11):2313-2339. https://doi.org/10.1111/jan.14078

Davies H, Coventry LL, Jacob A, Stoneman L, Jacob E. Blood sampling through peripheral intravenous cannulas: A look at current practice in Australia. Collegian. 2020;27(2):219-225. https://doi.org/10.1016/j.colegn.2019.07.010

Gorski LA, Hadaway L, Hagle ME, et al. Infusion Therapy Standards of Practice, 8th Edition. J Infus Nurs. Jan-Feb 01 2021;44(1S Suppl 1):S1-S224. https://doi.org/10.1097/NAN.0000000000000396

Hambleton VL, Gómez IA, Andreu FAB. Venipuncture versus peripheral catheter: do infusions alter laboratory results? J Emerg Nurs. 2014;40(1):20-26. doi:10.1016/j.jen.2012.03.014

Jacob A, Coventry L, Davies H, Jacob E. Are current clinical guidelines on the use of Peripheral Intravenous Cannula for blood draws supported by evidence? An organizational case study. Nurs Open. 2020;7(6):1746-1754. https://doi.org/10.1002/nop2.559

Jacob E, Jacob A, Davies H, et al. The impact of blood sampling technique, including the use of peripheral intravenous cannula, on haemolysis rates: A cohort study. J Clin Nurs. 2021;30(13-14):1916-1926. https://doi.org/10.1111/jocn.15744

Jacob ER, Jacob AM, Davies HT, Stoneman LJ, Coventry L. Peripheral intravenous cannulas for blood drawing: Nurses' views through content analysis. Collegian. 2021;28(4):408-414. https://doi.org/10.1016/j.colegn.2020.12.002

Jeong Y, Park H, Jung MJ, Kim MS, Byun S, Choi Y. Comparisons of laboratory results between two blood samplings: Venipuncture versus peripheral venous catheter-A systematic review with meta-analysis. J Clin Nurs. Oct 2019;28(19-20):3416-3429. https://doi.org/10.1111/jocn.14918

Lesser FD, Lanham DA, Davis D. Blood sampled from existing peripheral IV cannulae yields results equivalent to venepuncture: a systematic review. JRSM Open. May 2020;11(5):2054270419894817. https://doi.org/10.1177/2054270419894817

McCaughey EJ, Vecellio E, Lake R, et al. Key factors influencing the incidence of hemolysis: a critical appraisal of current evidence. Crit Rev Clin Lab Sci. 2017;54(1):59-72. doi:10.1080/10408363.2016.1250247

Twibell KR, Hofstetter P, Siela D, Brown D, Jones HM. A comparative study of blood sampling from venipuncture and short peripheral catheters in pediatric inpatients. J Infus Nurs. Sep/Oct 2019;42(5):237-247. https://doi.org/10.1097/nan.0000000000000338