The Larsson frequency/volume chart is not a substitute for cystometry in the investigation of women with urinary incontinence.

The aim of the study was to assess the ability of the Larsson chart nomogram to predict the presence of detrusor instability or genuine stress incontinence without recourse to cystometry. The Larsson chart provides a probability of detrusor instability by plotting 24-hour urinary frequency against the range of void volumes. Frequency/volume chart data were obtained from the records of 216 patients who had undergone subtraction cystometry. The Larsson chart was assessed by comparing the probability of detrusor instability or of genuine stress incontinence obtained with the cystometric diagnosis. The maximum sensitivity of the Larsson chart was 52%, with a specificity of 70% for detrusor instability. For genuine stress incontinence these figures were 66% and 65% respectively. The Larsson chart provides no diagnostic information and does not remove the need for formal cystometric evaluation of patients with urinary incontinence.