Diagnosing lactase deficiency in three breaths

Area of Science:

• Gastroenterology
• Diagnostic Medicine
• Biochemistry

Background:

• Lactose hydrogen breath tests (H(2)-BTs) are standard for diagnosing lactase deficiency, a common cause of lactose intolerance.
• Current H(2)-BT protocols involve frequent sampling, contributing to extended test durations.
• Optimizing sampling frequency is key to improving the efficiency of H(2)-BT.

Purpose of the Study:

• To evaluate the diagnostic accuracy of reduced-sample lactose H(2)-BTs.
• To compare the sensitivity and specificity of two- and three-sample H(2)-BTs against a standard, frequent-sampling protocol.

Main Methods:

• A retrospective analysis of 1049 lactose H(2)-BTs using a 15-minute sampling interval as the gold standard.
• Calculation of sensitivity, specificity, and predictive values for various two-sample (0-60, 0-90, 0-120 min) and three-sample (0-60-90, 0-60-120, 0-90-120 min) test protocols.

Main Results:

• The three-sample test (baseline, 60/90 min, 120 min) demonstrated high sensitivity (95.0%) and specificity (98.9-99.2%).
• Two-sample tests showed varying accuracy, with the 0-120 min protocol achieving 92.6% sensitivity and 99.2% specificity.
• A significant portion (32%) of the 1049 tests yielded positive results for lactase deficiency.

Conclusions:

• A three-sample lactose H(2)-BT (baseline, 60/90 min, 120 min) offers excellent sensitivity and specificity for diagnosing lactase deficiency.
• Lactose H(2)-BT protocols can be simplified, but the test duration cannot be reduced to less than 2 hours.
• Optimized sampling strategies enhance the efficiency of H(2)-BT for diagnosing lactose intolerance.