Functional constipation can be diagnosed using the Rome IV criteria.
Diagnostic criteria for functional constipation:
(1) >= 2 of the following:
(1a) straining in > 25% of defecations
(1b) lumpy or hard stools in > 25% of defecations
(1c) sensation of incomplete evacuation in > 25% of defecations
(1d) sensation of anorectal obstruction or blockage in > 25% of defecations
(1e) manual maneuver required in > 25% of defecations to facilitate the evacuation
(1f) < 3 spontaneous bowel movements per week
(2) occurrence of loose stools rare except with use of a laxative
(3) insufficient criteria for the diagnosis of irritable bowel syndrome (IBS)
Temporal criteria:
(4) symptoms present for >= 3 months
(5) onset of symptoms >= 6 months prior to diagnosis
where:
• Functional constipation is similar to opiate-induced constipation and the 2 conditions may overlap.