Diagnosis of occult blood in human feces using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry

BackgroundGuaiac-based chemical tests may be the most cost-effective for routine screening of fecal occult blood (FOB). Unfortunately, such approaches still suffer from the unreliability of the incidence of false-positive and false-negative results in subjects who are on an unrestricted diet. We developed a rapid, automatic, and reliable detection method for FOB using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF MS).MethodsThe water-soluble α- and β-chain hemoglobins (Hb), which are the most predominant proteins found in blood, were used as protein biomarkers for the diagnosis of FOB. The saturated 4-hydroxy-α-cyanocinnamic acid (α-CHC) solution was found to be the best MALDI matrix for Hb analysis.ResultsThe MALDI-TOF MS results were consistent with those provided through conventional chemical analysis, however, the sensitivity for the detection of FOB when using MALDI-TOF MS is approximately 10–100 times higher. In addition, the materials that commonly interfere with the conventional chemical assaying of FOB do not interfere with the detection of the Hb biomarkers during MALDI-TOF MS analysis.ConclusionsWe demonstrate that MALDI-TOF MS analysis of Hb biomarkers is an alternative approach toward the rapid diagnosis of FOB.