Effects of pH on glucose measurements with handheld glucose meters and a portable glucose analyzer for point-of-care testing

Arch Pathol Lab Med. 2000 Apr;124(4):577-82. doi: 10.1043/0003-9985(2000)124<0577:EOPOGM>2.0.CO;2.

Abstract

Objectives: To determine pH effects on glucose measurements obtained with the latest generation of glucose devices, to quantitate changes in glucose measurements obtained over a wide pH range, and to assess the potential clinical risks of pH effects with use of point-of-care glucose testing.

Design: Paired differences of glucose measurements between pH-altered and parallel control samples with target pH 7.40 were calculated.

Setting: A pH range of 6.94 to 7.84 was used to evaluate pH effects on glucose measurements in vitro with 6 handheld glucose meters and a portable glucose analyzer at both normal, 4.81 mmol/L (86.6 mg/dL), and high, 11.16 mmol/L (201 mg/dL), glucose levels.

Main outcome measures: Glucose measurements obtained from test samples and control samples were compared by calculating paired differences, which were plotted against pH to show pH effects on glucose meter measurements.

Results: At the normal glucose level, different pH levels did not interfere significantly with glucose measurements. At the high glucose level, a trend whereby low pH decreased and high pH increased glucose measurements was observed on the Precision G and the Precision QID glucose meters.

Conclusion: Because of potential risk in diabetic patients with ketoacidosis and in other patients with acid-base disorders, we recommend that clinicians choose glucose devices carefully and interpret the measurements cautiously when point-of-care glucose testing is performed in critically ill patients with acidemia, alkalemia, or changing acid-base status.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Chemical Analysis / instrumentation*
  • Blood Chemical Analysis / methods
  • Blood Gas Analysis / instrumentation
  • Blood Glucose / analysis*
  • Electrolytes / blood
  • Hematocrit
  • Humans
  • Hydrogen-Ion Concentration
  • Monitoring, Physiologic / instrumentation*
  • Monitoring, Physiologic / methods
  • Reproducibility of Results

Substances

  • Blood Glucose
  • Electrolytes