Although measurement of PVR is a common everyday occurrence in hospitalized patients, the threshold of what constitutes an abnormal value is often poorly defined and not standardized. However, most urologists consider volumes of 50 ml to 100 ml to constitute the lower threshold of abnormal PVR (1).
Large PVRs are associated with urinary tract infections, especially in persons at risk (e.g. diabetes, spinal cord injury), while very large PVRs (>300 ml) may be associated with an increased risk of upper urinary tract dilatation and renal insufficiency.
Chronic urinary retention is often defined as a PVR > 300 ml (2).
1. Kelly CE. Evaluation of voiding dysfunction and measurement of bladder volume. Rev Urol 2004;6 (suppl 1):S32-S37. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1472847
2. Kaplan SA, Wein AJ, Staskin DR, Roehrborn CG, Steers WD. Urinary retention and post-void residual urine in men: separating truth from tradition. J Urology 2008;180:47–54. https://www.ncbi.nlm.nih.gov/pubmed/18485378