Table 3.

Factors impacting the accuracy of self-monitored blood glucose.

	Falsely low BG results	Falsely high BG results	Variable impact on accuracy
USER ERROR
Improper handwashing	• Residual water on fingertips	• Traces of glucose-containing substances on fingertips • Residual alcohol on fingertips
Deteriorated test-strips			• Improper coding • Improper storage • Expired test-strips
AMBIENT CONDITIONS
Altitude			• High Altitude (>2,000 m)
Oxygen concentrations	• High partial pressure of oxygen	• Low partial pressure of oxygen
Extreme temperatures	• Cold temperatures (<10°C) • Rapid decrease in ambient temperature	• Rapid increase in ambient temperature	• Hot temperatures (>39°C)
Alternative test sites	• Testing at cold sites (e.g., forearm)		• Lag time created by decreased blood flow to alternative sites
PHYSIOLOGIC CONDITIONS AND MEDICATIONS
Laboratory values	• Elevated hematocrit (>45%) • Hypertriglyceridemia	• Low hematocrit (<35%) • Hyperuricemia
Altered tissue oxygenation	• Partial pressure of oxygen >150 mmHg* • Poor perfusion at testing site	• Partial pressure of oxygen <45 mmHg*
Medication related	• Ascorbic acid	• Acetaminophen • Maltose (in GDH-PQQ based devices only)

^*Glucose oxidase-based devices only.