A sensitive method of screening for urinary porphobilinogen

Area of Science:

• Biochemistry
• Clinical Chemistry
• Analytical Chemistry

Background:

• Porphobilinogen (PBG) is a key biomarker for acute intermittent porphyria (AIP).
• Current screening methods like Watson-Schwartz have limitations in sensitivity and specificity.
• Accurate and reliable PBG detection is crucial for timely diagnosis and management of porphyrias.

Purpose of the Study:

• To develop and evaluate a novel, highly sensitive, and specific screening method for urinary PBG.
• To compare the performance of the new resin-based method against the established Watson-Schwartz method.
• To assess the diagnostic utility of the resin method for detecting elevated PBG levels.

Main Methods:

• Urine samples were processed using a Dowex 2 resin adsorption technique under alkaline conditions.
• Adsorbed PBG was eluted with acid and reacted with Ehrlich's reagent for colorimetric detection.
• The resin method's performance was evaluated against the Watson-Schwartz method using samples with varying PBG concentrations.

Main Results:

• The resin method demonstrated 100% sensitivity at five times the upper limit of normal PBG, significantly outperforming the Watson-Schwartz method (51%).
• At lower PBG concentrations (just over and twice the upper limit), the resin method achieved 97% and 100% sensitivity, respectively.
• The resin method exhibited 100% specificity, compared to 95% for the Watson-Schwartz method, with no false positives in normal urine samples.

Conclusions:

• The Dowex 2 resin-based screening method for urinary PBG is highly sensitive, specific, and reliable.
• This novel method offers significant advantages over the Watson-Schwartz screening test.
• The resin method represents a superior tool for the accurate detection of urinary porphobilinogen.