Blood Glucose Monitoring

Blood glucose monitoring is an essential component of diabetes management and patient care. It entails measuring the blood’s glucose (sugar) levels to ensure they stay within a desired range. This practice is vital for effective diabetes control and the prevention of complications. Below is a detailed guide on blood glucose monitoring, nursing procedures, and step-by-step instructions.

Table of Contents

• What is Blood Glucose?
• Capillary Blood Glucose Specimen
• Key Points
• Importance of Blood Glucose Monitoring
• Contraindications for Obtaining a Capillary Blood Specimen
• Procedure in Obtaining a Capillary Blood Specimen to Measure Blood Glucose
  • Assessment
  • Delegation
  • Implementation
  • Evaluation
• References

What is Blood Glucose?

Blood glucose, also known as blood sugar, refers to the concentration of glucose present in the blood. Glucose is a type of sugar that serves as the primary source of energy for the body’s cells. It is derived mainly from the carbohydrates in the food we eat, and it circulates through the bloodstream to provide energy to cells throughout the body.

Capillary Blood Glucose Specimen

A capillary blood specimen is used to measure current blood glucose levels, particularly when frequent testing is needed or when venipuncture isn’t feasible. This method is less painful than venipuncture and is simple enough for patients to perform on their own.

The development of home glucose test kits and reagent strips has made blood glucose testing more accessible, greatly aiding in the self-management of diabetes. Various manufacturers have also developed blood glucose meters or monitors to further simplify the process.

Key Points

Here are some important points about blood glucose.

1. Source of Energy. Glucose is essential for cellular function, particularly in organs like the brain, which relies heavily on glucose for energy.

2. Regulation of Blood Glucose Levels. The body maintains blood glucose levels within a narrow range through the actions of two key hormones produced by the pancreas:

• Insulin. Lowers blood glucose levels by facilitating the uptake of glucose into cells and storing excess glucose in the liver as glycogen.
• Glucagon. Raises blood glucose levels by stimulating the liver to release stored glucose back into the bloodstream.

3. Normal Blood Glucose Levels. Normal blood glucose levels are essential for maintaining the body’s overall health and proper functioning.

• Fasting blood glucose levels (after 8 hours without food) typically range between 70 and 99 mg/dL.
• Postprandial blood glucose levels (2 hours after eating) should be less than 140 mg/dL.

4. Conditions Related to Blood Glucose Levels. High and low blood glucose levels, known as hyperglycemia and hypoglycemia respectively, can have significant health implications if not managed properly.

• Hyperglycemia. High blood glucose levels, often associated with diabetes. It can lead to complications such as diabetic ketoacidosis, nerve damage, and cardiovascular problems.
• Hypoglycemia. Low blood glucose levels, which can cause symptoms like shakiness, confusion, sweating, and, in severe cases, seizures or unconsciousness.

5. Types of Glucose Monitors.

• Glucometers. Portable devices that measure blood glucose from a small blood sample.
• Continuous Glucose Monitors (CGMs). Devices that provide real-time glucose readings through a sensor placed under the skin.

Importance of Blood Glucose Monitoring

The following are the importance of blood glucose monitoring:

1. Prevents Complications. Regular monitoring helps maintain blood glucose levels within a target range, reducing the risk of complications such as neuropathy, retinopathy, kidney disease, and cardiovascular problems.
2. Guides Treatment Adjustments. Monitoring provides real-time data that allows for timely adjustments to insulin, medications, diet, and exercise, ensuring optimal glucose control.
3. Enhances Patient Awareness. It empowers patients to understand their glucose patterns, leading to better self-management of diabetes and more informed lifestyle choices.
4. Detects Hyperglycemia and Hypoglycemia Early. Early detection of abnormal blood glucose levels allows for prompt intervention, preventing severe episodes of hyperglycemia or hypoglycemia.
5. Improves Long-term Health Outcomes. Consistent blood glucose monitoring contributes to better long-term control of diabetes, which is associated with improved overall health and reduced healthcare costs.
6. Supports Individualized Care Plans. Monitoring results help healthcare providers tailor treatment plans to the individual needs of each patient, considering their unique response to therapies.
7. Assists in Evaluating the Effectiveness of Treatment. Regular monitoring allows patients and healthcare providers to assess how well current treatments are working, leading to adjustments if necessary to achieve better glucose control.
8. Helps Manage Acute Illnesses or Stress. Blood glucose levels can fluctuate during illness or stress; monitoring ensures that these fluctuations are managed promptly to avoid complications.
9. Aids in the Prevention of Diabetes-related Emergencies. By identifying and addressing blood glucose extremes, monitoring can prevent emergencies such as diabetic ketoacidosis (DKA) or severe hypoglycemia, which require urgent medical attention.
10. Facilitates Better Communication with Healthcare Providers. Documented glucose levels provide essential information during medical appointments, allowing for more accurate assessments and decision-making.

Contraindications for Obtaining a Capillary Blood Specimen

By avoiding these contraindications, healthcare providers can ensure that capillary blood glucose measurements via glucometer are accurate and safe for the patient.

1. Severe Edema. Edematous tissue may result in a diluted blood sample due to excess fluid, leading to inaccurate glucose readings.
2. Infection or Inflammation at the Puncture Site. Sampling from an infected or inflamed area increases the risk of spreading infection and can compromise tissue integrity, affecting the accuracy of the test.
3. Poor Peripheral Circulation (e.g., in Shock or Severe Hypotension). Reduced blood flow in these conditions can result in an insufficient blood sample or inaccurate readings due to altered capillary perfusion.
4. Heavily Callused or Scarred Skin. Callused or scarred areas may prevent adequate blood flow or sample collection, leading to inaccurate glucose readings or difficulty obtaining the sample.
5. Raynaud’s Disease or Other Peripheral Vascular Disorders. These conditions cause vasoconstriction and decreased blood flow to extremities, making it difficult to obtain a reliable blood sample for glucose testing.
6. Recent Surgery on Hands or Fingers. Performing a fingerstick in areas of recent surgery can interfere with healing, increase discomfort, and pose a risk of infection.
7. Extremely Low Hematocrit Levels. Low hematocrit can affect the accuracy of glucose readings, as some glucometers are less reliable when a low red blood cell count alters blood composition.
8. Severe Dehydration. Dehydration reduces blood volume, making it difficult to obtain a sufficient capillary blood sample and potentially leading to inaccurate glucose readings.
9. Venous Congestion or Impaired Lymphatic Drainage. These conditions may alter the composition of capillary blood and lead to false readings due to the accumulation of fluids.
10. Excessive Sweating or Moisture on the Skin. Moisture at the puncture site can dilute the blood sample or interfere with the glucometer, leading to unreliable results.

Procedure in Obtaining a Capillary Blood Specimen to Measure Blood Glucose

The following steps outline the procedure for obtaining a capillary blood specimen to measure blood glucose.

Assessment

Before obtaining a capillary blood specimen, the following steps should be taken, each with its corresponding rationale:

1. Review the facility’s policies and procedures.
Ensuring familiarity with the facility’s guidelines helps maintain consistency and compliance with institutional standards for blood glucose testing.

2. Determine the frequency and type of testing required.
Understanding the specific testing schedule and method ensures that the patient’s blood glucose levels are monitored appropriately, avoiding unnecessary or missed tests.

3. Assess the patient’s understanding of the procedure.
Verifying the patient’s comprehension ensures that they are informed and can cooperate fully, which can reduce anxiety and improve the accuracy of the test.

4. Evaluate the patient’s response to previous testing.
Reviewing past reactions, such as pain or anxiety, allows the nurse to address any concerns and modify the approach if necessary to improve patient comfort.

5. Examine the puncture site for skin integrity and circulation.
Checking the skin for intactness, color, warmth, and capillary refill ensures that the site is suitable for puncture, reducing the risk of infection and ensuring accurate results.

6. Review the patient’s record for medications that may prolong bleeding, such as anticoagulants, and medical conditions that may increase bleeding risk.
Identifying these factors beforehand helps in planning appropriate precautions to prevent excessive bleeding during and after the procedure.

7. Assess the patient’s self-care abilities, such as visual acuity and finger dexterity, which may affect the accuracy of the test.
Ensuring that the patient can correctly perform the test, or providing assistance if needed, is crucial for obtaining reliable results and effective diabetes management.

Delegation

In many settings, nurses delegate BGM tasks to licensed practical nurses (LPNs) or nursing assistants (CNAs), depending on the scope of practice.

1. Check the applicable nurse practice act and the facility’s policy and procedure manual to determine who is authorized to perform this skill.
Since it is typically regarded as an invasive procedure requiring problem-solving and application of knowledge, the nurse must be aware of the test results and oversee any unlicensed assistive personnel (UAP) assisting with the task.

2. Provide clear instructions when delegating BGM tasks.
Nurses must provide clear instructions on the patient’s monitoring schedule, critical values that require immediate notification, and documentation procedures.

3. Ensure competency.
Before delegating, nurses must verify that the personnel have the necessary skills and training to perform BGM accurately and safely. This includes understanding how to use the equipment, troubleshoot issues, and recognize abnormal readings.

Implementation

Accurate and timely blood glucose monitoring is essential for preventing complications and achieving optimal patient outcomes. Below is the step-by-step procedure for obtaining a capillary blood sample to measure blood glucose levels.

1. Prior to performing the procedure, introduce self and verify the patient’s identity using agency protocol. Explain to the patient what you are going to do, why it is necessary, and how they can participate. Discuss how the results will be used in planning further care or treatments.
Ensures accurate patient identification, promotes patient understanding, and fosters cooperation and participation in care.

2. Perform hand hygiene and don gloves.
Reduces the risk of infection for both the nurse and the patient, following standard infection control practices.

3. Ensure that the glucometer, test strips, and lancet are ready and functioning properly.
Ensuring the equipment is in good working order prevents errors in the blood glucose reading and minimizes patient discomfort due to repeated attempts.

4. Select the appropriate site for capillary blood sampling (usually the side of the fingertip).
The sides of the fingertips are less sensitive than the central pad and have a good blood supply, making them ideal for capillary sampling.

5. Clean the selected site with an alcohol swab and allow it to air dry.
Cleaning the site reduces the risk of infection, and allowing it to air dry ensures alcohol does not interfere with the glucose reading.

6. Hold the patient’s finger below the level of the heart and gently massage or “milk” the finger to encourage blood flow (if needed). Avoid excessive squeezing.
Holding the finger below heart level and massaging promotes blood flow to the area, while excessive squeezing may dilute the blood sample with tissue fluid, leading to inaccurate results.

7. Use a sterile lancet to prick the side of the fingertip.
Using a sterile lancet ensures a clean puncture, minimizing the risk of infection and providing an adequate blood sample for accurate testing.

8. Gently squeeze the finger, if necessary, to obtain a drop of blood large enough to cover the test strip.
Ensures an adequate sample for the glucometer to read accurately.

9. Place the drop of blood on the test strip according to the manufacturer’s instructions and insert the strip into the glucometer (if not already inserted).
Following manufacturer guidelines ensures the test is performed correctly and results are reliable.

10. Wait for the glucometer to display the result and document the blood glucose reading.
Timely documentation ensures accurate record-keeping and provides the healthcare team with essential information to guide treatment.

11. Dispose of the lancet and test strip in a sharps container and any other waste in an appropriate biohazard container. Remove gloves and perform hand hygiene.
Proper disposal of sharps and biohazard materials minimizes the risk of injury or contamination. Hand hygiene prevents the spread of infection.

12. Provide comfort measures and ensure the patient is comfortable. Thank them for their cooperation.
Promoting patient comfort and expressing gratitude enhances the therapeutic relationship and encourages continued cooperation.

13. Report critical blood glucose levels to the appropriate healthcare provider immediately.
Prompt reporting of abnormal values allows for timely medical interventions, reducing the risk of complications such as hypoglycemia or hyperglycemia.

14. Check for orders for sliding scale insulin based on capillary blood glucose results. Administer insulin as prescribed.
Administering insulin according to sliding scale orders ensures proper glucose control and helps prevent further complications associated with blood sugar imbalances.

Evaluation

1. Compare the glucose meter reading with normal blood glucose levels, assess the puncture site, and evaluate the patient’s motivation to perform the test independently.
This helps to ensure the reading is within the expected range, checks for any complications at the puncture site, and assesses the patient’s readiness to take an active role in their own care.

2. Relate the current blood glucose reading to previous readings and consider the patient’s overall health status.
Monitoring trends in glucose levels provides context for the current reading, allowing for a more comprehensive assessment of the patient’s glycemic control and overall condition.

3. Report abnormal results to the primary care provider. Some facilities may have a standing policy to perform a venipuncture blood glucose test if capillary readings exceed a certain threshold.
Timely reporting of abnormal values allows for prompt medical intervention and further testing, ensuring accurate diagnosis and treatment.

4. Conduct appropriate follow-up by asking the patient to explain the significance of the results or demonstrate the procedure at the next scheduled test.
This reinforces the patient’s understanding of their condition and helps ensure they can accurately perform blood glucose testing, promoting better self-management.

5. Prepare the patient for home glucose monitoring by reviewing testing frequency, record keeping, and insulin administration, if applicable.
Proper education on home monitoring, documentation, and insulin use empowers the patient to effectively manage their diabetes, enhancing self-care and improving long-term outcomes.

References

• Berman, A., Snyder, S. J., & Frandsen, G. (2015). Kozier & Erb’s fundamentals of nursing: Concepts, process, and practice (10th ed.). Pearson.
• Mathew TK, Zubair M, Tadi P. Blood Glucose Monitoring. [Updated 2023 Apr 23]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555976/