Detection of polyethylene glycol-based laxatives in stool

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Pediatric Gastroenterology

Background:

• Testing stool for laxatives is vital in specific clinical scenarios.
• Surreptitious laxative administration or non-adherence can complicate patient care, particularly in pediatric constipation.
• Existing laboratory methods do not detect polyethylene glycol (PEG)-based laxatives, a common treatment for childhood constipation.

Purpose of the Study:

• To develop and validate a mass spectrometry (MS)-based assay for detecting PEG in stool samples.
• To pilot this new diagnostic tool in a clinical setting involving children.

Main Methods:

• Development of a novel mass spectrometry (MS) technique for PEG detection in stool.
• Verification of the MS assay in an adult volunteer.
• Pilot study comparing MS results from children receiving PEG for constipation versus children with diarrhea.

Main Results:

• The MS assay successfully detected PEG in the stool of all children receiving PEG laxatives (7/7).
• None of the children with diarrhea (not taking PEG) tested positive for PEG by MS (0/9).
• Subjects receiving PEG showed elevated stool osmolal gaps, consistent with PEG ingestion.

Conclusions:

• A reliable MS-based method for stool PEG detection has been established.
• This assay can aid in confirming surreptitious PEG administration.
• The methodology offers a valuable tool for evaluating treatment efficacy and failure in pediatric constipation management.