Can Redesigning a Laboratory Request form Reduce the Number of Inappropriate PSA Requests without Compromising Clinical Outcome

Abstract

Introduction:

Unnecessary laboratory utilization due to inappropriate test-ordering behaviour among hospital clinicians and community general practitioners is an ongoing problem in many hospitals and primary care trusts throughout the UK and abroad. In January 2007, our hospital removed the ‘tick box’ for PSA from its laboratory tests request form, in a managed way, with the intention of reducing unnecessary requests for this test. Here we address the impact this action had on the number of PSA tests being requested and its downstream effects on prostate cancer diagnosis.

Methods:

Using our laboratory database we compared the number of hospital and local GP requests for PSA, before and after modification of our laboratory form (requests from 2004 to 2006 were compared to 2007). We then correlated this data with the number of fast-track target referrals (2 week wait) from primary care for suspected prostate cancer, the results of prostate biopsies, and the number of prostate cancers being diagnosed, over the same time period.

Results:

Mann—Whitney non-parametric testing demonstrated a 17% reduction in the median number of PSA requests since the change was introduced (p = 0.001). Subset analysis revealed an 18% reduction in GP requests (p = 0.002). However no change was found in the number of prostate cancer diagnoses being made (p = 0.86) and the number of target referrals for suspected prostate cancer (p = 0.59) in the months of April, May, June, July, August and September of 2004–2006 as compared to the same months in 2007. The rate of patients undergoing biopsy increased in the post intervention period from 15.5 to 18.5 patients per month. The rate of negative biopsies remained stable, changing from 7.2 to 7.3 per month, and the rate of positive biopsies increased from 8.3 to 11.2 per month. This change reduced the false negative rate (suspected cancer, negative biopsy) from 46% to 40% in the period following the intervention. The rate of target referrals leading on to cancer showed a small increase after the intervention from 2.9 to 3.3 per month.

Conclusions:

Our study shows that with this simple modification to the design of our laboratory request form, whereby the doctor must make an active written decision to order a PSA test, there was a significant reduction in the number of PSA requests, both in the hospital and in the community, without patient safety being compromised as measured by maintaining the number of fast-track target referrals for suspected prostate cancer and the number of prostate cancers diagnosed.