How do you confirm a patient's insulin use?

How to Check if a Patient is Injecting Insulin

To confirm a patient's insulin use, examine their injection sites for lipohypertrophy (tissue swelling) or lipoatrophy (tissue depression), check their blood glucose patterns, and inspect their insulin supplies for proper storage and usage patterns.

Physical Examination Approach

• Examine injection sites (abdomen, thighs, upper arms, and buttocks) for signs of lipohypertrophy or lipoatrophy, which occur in approximately 30% of insulin users and indicate repeated injections 1
• Look for needle marks, bruising, or redness at common injection sites 2
• Observe for rotation patterns within injection areas, as proper rotation is recommended to prevent tissue changes 2
• Note that the abdomen has the fastest rate of absorption, followed by the arms, thighs, and buttocks - this pattern of use may be visible 2

Blood Glucose Pattern Analysis

• Review blood glucose monitoring records for patterns consistent with insulin administration 2
• Look for unexplained hypoglycemic episodes, which may indicate insulin use 2
• Check for glycemic variability, which is more common in patients using insulin, especially those with lipohypertrophy 1
• Monitor for patterns of low blood glucose corresponding to expected peak insulin action times 2

Insulin Supply Inspection

• Inspect the patient's insulin vials or pens for:
  • Proper storage (refrigeration for unopened vials, room temperature for in-use supplies) 2, 3
  • Signs of use such as diminishing volume in vials 2
  • Expiration dates and dates when vials were opened 2, 3
  • Visual changes in insulin appearance (clumping, frosting, precipitation, or color changes) 2
• Check for the presence of insulin administration supplies:
  • Syringes or pen needles 3
  • Alcohol swabs for site cleaning 4
  • Proper sharps disposal containers 2

Patient Interview and Demonstration

• Ask the patient to demonstrate their insulin injection technique 4
• Verify their knowledge of:
  • Proper mixing technique for cloudy insulins 2
  • Correct injection angle (90° for most patients, 45° for thin individuals) 2
  • Site rotation practices 2
  • Insulin storage methods 2
• Request that patients bring all their diabetes supplies to appointments for verification 4

Laboratory Confirmation

• Order C-peptide levels, which will be low or absent in type 1 diabetes patients using exogenous insulin 5
• Monitor HbA1c levels for changes that would be consistent with insulin therapy 1
• Consider checking for insulin antibodies in cases where verification is critical 5

Common Pitfalls to Avoid

• Don't rely solely on patient self-reporting, as adherence to insulin regimens is often overestimated 1
• Remember that improper injection technique is common - 51.43% of patients don't mix insulin properly before injection 4
• Be aware that many patients (approximately 10%) report never receiving proper training on injection technique despite using insulin for years 1
• Avoid assuming proper disposal practices - 91% of patients improperly dispose of needles and syringes 4
• Don't overlook the importance of regular site inspection - this is associated with better glycemic control and less lipohypertrophy 1