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Eight Questions Every Phlebotomist MUST Answer Correctly: #2

Do you always insert the needle at a low angle of insertion?

by Dennis Ernst • February 05, 2021


Blood draw angle of insertion for venipuncture

Question #2: Do you always insert the needle at a low angle of insertion?

One of the most dangerous errors collectors make is to enter the vein at a high angle of insertion. 

Remember, veins are not very large in diameter. When entering the skin at an excessive angle, the needle is much more likely to go through the vein and into underlying structures at a high angle than if the angle of insertion is low. A lower angle provides a greater margin of error in the depth of penetration. Low angles provide us with some "breaking distance" before we are through the other side of the vein. When the needle is inserted at an excessive angle, the patient is at risk of injury because there is almost no margin for error in the depth of penetration. Because we must rely on our instinct and skill about the depth to which the needle should be inserted, we must give ourselves and our patients every advantage in keeping the needle from going through the other side of the vein. With this in mind, remember: the lower the angle of insertion, the greater the advantage. According to CLSI and most textbooks, the proper angle of insertion is 30 degrees or less.

If a patient is injured and it can be shown that the angle of insertion was excessive, the facility may be liable for the injury. In one case, a patient who was injured during a venipuncture estimated the angle of needle insertion to be 70-degrees. The phlebotomist's supervisor claimed it was only 40-degrees, and testified it to be an acceptable angle. The patient’s attorney cited publication after publication stating a 15- to 30-degree angle of insertion constituted an acceptable angle, yet the supervisor testified that at her facility a 40-degree angle was acceptable. Finally, the attorney read from the laboratory’s own procedure manual, which reflected the standards. In this trial, the patient’s attorney built a convincing case that the facility considered itself immune from the standard of care, even from their own procedures, by supporting an angle of insertion greater than 30 degrees.

In another case, a phlebotomist attempted to access the basilic vein at 90 degrees and inflicted a permanent nerve injury. The patient successfully sued the hospital.

Because the standards and textbooks clearly define the proper angle of insertion when performing a venipuncture, the evidence is overwhelmingly against deviations. If you teach venipunctures, realize that many of your students won't know what 30 degrees looks like, so simply stating the limit may not be enough. Consider taking a digital image of what a 30-degree angle looks like and put it in their course materials or in a slide presentation. The CLSI venipuncture standard (GP41) has an illustration that might be helpful. In the absence of a visual, simply instruct your staff or students to enter the skin at the lowest angle possible. There is no minimum angle of insertion in the standards, only a maximum.

Correct answer: I always insert the needle into the skin at an angle of 30-degrees or less, which is according to the standards and our facility policy.

If you've answered this question correctly, congratulations. Make sure everyone in your facility can, too. Use this series of questions as a point of discussion at your next departmental or staff meeting. Your coworkers may already know the correct answer, but reminders are a good way to reinforce good phlebotomy practices. In a few days, I'll post Question #3.

In case you're interested, I've compiled all eight questions into one of our most popular downloads, "Eight Questions Every Phlebotomist Must Answer Correctly."

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angle of insertion CLSI GP41 YouTube needle


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