Blood glucose testing: Clinical skills notes

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Notes

Endocrine

Blood glucose testing

INTRODUCTION
Blood glucose testing (Fig. 1) is a procedure in which a client's blood glucose level is measured using a small, portable device called a glucometer. It requires a drop of capillary blood, most commonly obtained from a finger, and takes a few seconds to show results. This is especially important for people with diabetes mellitus type 1 and type 2, as well as gestational diabetes mellitus (GDM). Regular blood glucose testing evaluates the effects of medications, diet, and exercise on keeping blood glucose levels under control. This will prevent future complications like vision impairment, kidney and nerve damage, and cardiovascular disease.
Figure 1: Blood glucose testing.
COMMON CARE TIPS
  • Be sure to follow your facility’s policies and/or protocols. Also, make sure to familiarize yourself with the type of glucose meter used at your facility. 
  • Determine the most appropriate site for a puncture; your clients might have thickened, damaged, edematous, or inflamed areas of skin.
  • Check the plan of care to determine how often a client needs their blood glucose checked and what their normal range is. 
    • Some clients will need testing only once a day, while others might need it more than once and at specific times, like before meals or drug administration. 
  • Clients who have coagulation disorders or take drugs that can alter bleeding time might take longer to stop the bleeding after the procedure. 
PROCEDURE
Before you perform blood glucose testing, gather the necessary supplies, including:
  • gloves
  • lancet device
  • antiseptic swab
  • washcloth
  • cotton or gauze
  • glucometer and reagent strips
    • Make sure you read the instructions on how to use a glucometer because some steps might differ depending on the manufacturer
Figure 2: Necessary supplies for blood glucose testing.

For the procedure

  • Make sure your client is comfortably sitting or lying in bed in the semi-Fowler position (Fig. 3a). If they’re in bed, lock the wheels, raise it to a height that’s comfortable to work with, and lower the side rails. 

  • Take a new reagent strip and place it in the glucometer to activate it (Fig. 3b). Make sure that the reagent strip is not expired or discolored and that it’s the right kind of strip for the glucometer.

  • Next, prepare the lancet device, which could be one-use or multi-use. In general, you’ll need to remove the cap of the device and adjust the depth of the puncture depending on the thickness of the client’s skin (Fig. 3c).

  • Put on gloves before looking for the best place to puncture; an ideal spot would be the side of a finger (Fig. 3d). 

    • Avoid the fingertips because they usually have thicker skin. Also, avoid any calloused or bruised areas and puncture sites of previous tests. 

Figure 3: Preparation before blood glucose monitoring procedure.

Procedure

1. Warm up the finger with a warm washcloth and hold it below the client’s heart level to increase blood flow to the finger (Fig. 4).

2. Clean the area with an antiseptic swab, and let it dry.

3. Place the tip of the lancet device on the chosen site, hold it steady, and press the button to release the lancet and puncture the skin. After you remove the device, you should see a drop of blood-forming. Press gently on the skin next to the puncture site to squeeze out more blood if you need to. 

Figure 4: Procedures for blood glucose monitoring (step 1–3).

4. Take the glucometer with a strip and place the tip of the strip to the blood drop. The blood should be automatically drawn in and the glucometer will inform you when enough sample is collected (Fig. 5).

5. While you wait for the results to appear on the screen, you should put a cotton ball or gauze square on the punctured site and keep applying pressure until the bleeding stops.

6. Read the result and share it with the client. 

7. After you’re done, turn off the glucometer; discard the strip, cotton or gauze, and gloves; and throw away the lancet in the sharps container. Return the other equipment for proper storage. 

Figure 5: Procedures for blood glucose monitoring (step 4–7). 
DOCUMENTATION
When performing a blood glucose test, you should report the following to the healthcare provider:
  • bleeding that doesn’t stop after at least five minutes of pressure 
  • abnormal results

Document:

  • date and time of testing
  • puncture site
  • test results
  • any abnormal observations
Author: Vanja Savić, MD
Editor: Lisa Miklush, PhD, RN, CNS
Editor: Jodi Berndt, PhD, RN, CCRN-K, PCCN-K, CNE, CHSE
Editor: Jannah Amiel, MS, BSN, RN
Illustrator: Talia Riley, MSMI
Illustrator: Jung-Hee Lee, MScBMC