Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement for medtech innovation briefings. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting

Published evidence

There is 1 study summarised in this briefing, including 63 people.

This non‑comparative prospective observational study was reported in abstract form only.

The clinical evidence and its strengths and limitations is summarised in the section on overall assessment of the evidence.

Overall assessment of the evidence

The evidence is of low methodological quality and has small patient numbers. No comparative studies were identified, and none were done in the UK. The study shows that measuring urine output using RenalSense Clarity RMS can identify acute kidney injury (AKI) sooner than by using serum creatinine. The evidence came from 1 conference abstract so more high‑quality research is needed comparing RenalSense Clarity RMS with standard care, in more patients. There is a further study measuring urine output accuracy compared with standard care but this is not for patients at risk of AKI, so is not included here.

Goldman et al. (2017)

Intervention and comparator

RenalSense Clarity RMS with urometer.

Key outcomes

The patients were split into 3 groups based on the kidney disease: improving global outcomes (KDIGO) criteria: serum creatinine only, urine output only and serum creatinine plus urine output. Results were reported for patients with AKI compared with patients without AKI. Length of stay in the intensive care unit (ICU) in the serum creatinine only (p≤0.0023), urine output only (p≤0.0074) and serum creatinine plus urine output groups (p≤0.0018) was statistically significantly longer for people with AKI than people without AKI. There were 13 people in the AKI serum creatinine plus urine output group (12 with AKI urine output stage 2, and 1 with stage 1). AKI was identified as much as 120 hours earlier by urine output than by serum creatinine. In all 3 methods, AKI patients had significantly more fluid in the first 24 hours of urine output monitoring than those without AKI.

Strengths and limitations

The authors conclude that monitoring urine output in real time will provide valuable information to identify AKI earlier, intervene earlier, and set protocol goals such as decisions for timely fluid and diuretic administration as well as evaluating response. The accuracy of the sensor was validated using a scientific scale and then the validated RenalSense Clarity RMS was used to measure urine flow. The urometer was incorporated into the RenalSense Clarity RMS sensor kit so that nurses could record urine output as per standard practice. The staff were blinded to both Clarity RMS and scale measurements. However, comparative results were not presented. This study is reported in conference abstract form only and is limited in detail. All apart from 1 study author are employees of RenalSense.


The sensors are for single patient use and are disposed of in clinical waste as per similar products.

Recent and ongoing studies

The company is aware of 2 additional studies that are yet to be published.