Taking Blood from IV Cannula

Many medical procedures involve the collection of blood samples for diagnostic purposes. One common method is to extract blood directly from an IV cannula. This procedure offers significant advantages, such as ease of access and decreased patient discomfort. In this blog post, we will explore the technique of taking blood from an IV cannula and discuss the proper steps to ensure a successful blood draw.

Step 1: Prepare the equipment

Before starting the blood collection, it is crucial to gather all the necessary equipment. This includes sterile gloves, alcohol swabs, a tourniquet, a blood collection tube, a needle adapter, and a syringe. Ensure that the equipment is readily accessible and in good condition to maintain a sterile environment.

Step 2: Verify patient identification

Patient identification is of utmost importance throughout any medical procedure. Before proceeding, confirm the patient’s identity by checking their identification bracelet or asking them to state their full name and date of birth. This step ensures accurate labeling of the collected blood samples.

Step 3: Apply sterile gloves

Prior to handling the IV cannula and collection equipment, put on a pair of sterile gloves to minimize the risk of contamination. Ensure that the gloves fit properly and cover the entire hand and wrist.

Step 4: Cleanse the puncture site

Select an appropriate site for blood collection and cleanse it using an alcohol swab. Start from the center and clean in a circular motion, gradually moving outward. Allow the area to air dry completely before proceeding.

Step 5: Apply the tourniquet

Apply a tourniquet a few inches above the intended puncture site. This will help the veins swell and become more visible, making it easier to locate and access them during the blood draw.

Step 6: Prepare the blood collection tubes

Choose the appropriate blood collection tube(s) based on the tests required. Attach the needle adapter to the syringe and ensure it is secured tightly. This will allow blood to flow directly into the collection tubes.

Step 7: Perform the blood draw

With the cannula securely in place, slowly insert the needle into the vein at a slight angle, taking care not to puncture through the opposite vein wall. Once the needle is correctly positioned, blood should flow easily into the syringe. Gently aspirate the required amount of blood into the collection tubes.

Step 8: Safely remove the equipment

After the blood draw is complete, carefully remove the tourniquet and release any pressure. Withdraw the needle from the cannula slowly, simultaneously applying pressure to the puncture site with a sterile gauze pad. Dispose of the used syringe and needle safely in a sharps container.

Step 9: Properly label the blood samples

Accurate labeling is crucial to prevent sample mix-ups. Immediately after the blood draw, ensure the collection tubes are labeled with the patient’s name, date, and time of collection. Use clear and legible handwriting or print labels to minimize errors.

Step 10: Document the procedure

Record the blood collection procedure in the patient’s medical chart, including any complications or noteworthy observations. This step ensures accurate documentation and follow-up care if needed.


Taking blood samples from an IV cannula is a routine procedure in healthcare settings. By following the aforementioned steps with precision and adhering to strict hygiene practices, healthcare professionals can safely and efficiently collect blood for diagnostic purposes. Remember to always prioritize patient safety and comfort throughout the entire procedure.

Leave a Comment