Use of Blood Urea Test in General Practice

1 April 2015 – 31 March 2016

Practice Points

Although blood urea provides a measure of kidney function, it is not necessary to evaluate stable kidney function.

Serum creatinine and estimated GFR (eGFR) is sufficient to evaluate stable kidney function.

In acute kidney injury, blood urea may be useful to assess the cause. Urea that is disproportionately high compared to the rise in creatinine may be seen in conditions where there is volume depletion, hypercatabolism or bleeding into the upper GI tract.

Test Results for Out-Patients

1 April 2015 – 31 March 2016

In general practice, blood urea is usually ordered with serum creatinine, and is unnecessary in stable patients.

Creatinine, eGFR, and Urea Test Results, Separately

eGFR vs Urea for Out-Patients

1 April 2015 – 31 March 2016

High blood urea with normal eGFR in stable patients creates unnecessary diagnostic confusion.

Blood Urea in Out-Patients with Normal eGFR

1 April 2015 – 31 March 2016

15.8% of people with normal eGFR have elevation in blood urea, but rarely above 10 mmol/L.

Top 20 General Practitioners by Volume of Blood Urea Test

1 April 2015 – 31 March 2016