The accuracy of the frequency-volume chart: comparison of self-reported and measured volumes

OBJECTIVE: To assess the accuracy of frequency-volume charts recorded by patients with voiding symptoms by comparing self-reported voiding data with the volumes of urine collected in same period.

PATIENTS AND METHODS: The study comprised 18 patients (median age 63 years, range 20-80) and lasted 3 days, during which the patients recorded their fluid intake and voided volumes, and collected 24 h urine samples.

RESULTS: The recorded volumes exceeded or underestimated the collected volume in 49% and 51%, respectively, of the samples, but the agreement between the accumulated daily voiding volumes on the charts and the volumes collected was acceptable. The median difference between volumes recorded on the charts and collected as samples was 100 (0-1450) mL per 24 h or 10 (0-117) mL per voiding (not significant). The median daily variation of creatinine in the urine was 1.1 (0.1-9.4) mmol (not significant), indicating that the 24 h collection periods were respected.

CONCLUSION: Recordings on frequency-volume charts are valid and useful in the investigation of patients with voiding symptoms.