Assessment of the Effect of Regular Audit and Feedback with Peer Comparison on Daily Lab Ordering Habits

From the 2019 HVPAA National Conference

Dr. Walid El-Nahal (University of Virginia), Mr. Garret Rhodes (University of Virginia), Dr. Andrew Parsons (University of Virginia)


The focus of our project is on studying methods to safely reduce unnecessary lab ordering. Daily lab ordering data collected at our institution on the ten months leading up to our project shows that on average, the number of labs collected per patient per day are as follows (charge per test in parenthesis): 0.88 (CBC, $88), 0.16 (CBC with Differential, $120), 0.97 (BMP, $190), 0.21 (CMP, $334), 0.52 (Magnesium, $84), and 0.36 (Phosphorus, $64).


Our hypothesis is that regular feedback with peer comparison to providers on ordering habits would reduce daily labs ordered. We implemented a project aimed at testing this on general medicine teams.


Our general medicine service is composed of 6 resident teams (one resident and one intern each). New trainees rotate on every 3 weeks (at different weeks for each team). Using our electronic medical record (Epic) we are able to collect data for each of the six teams on the number of complete blood counts (CBC), basic metabolic panels (BMP), liver function tests (LFT), Magnesium (Mg), and Phosphorus (Ph) labs ordered per patient per day. Three of the teams (intervention arm) received a weekly e-mail showing their lab ordering habits in real time. It showed the number of times each lab was ordered per patient per day for the prior 3 weeks. The averages for the other two intervention teams were provided as well for comparison. The average number of daily labs ordered by the three intervention arm teams was then compared to the three control arm teams. We compared the intervention arm to the control arm over a three month average as well as a five month average. We compared the intervention arm post-intervention to itself pre-intervention, looking at an average of lab ordering of 3 months pre and post as well as 5 months pre and post. Of note, the institution began an incentive project to reduce housestaff CBC ordering partway through our study which confounds results for that test.


Comparing control versus intervention respectively using z-tests over a 3 month period, the results were CBCs 0.703 vs 0.580(p=5.1*10^-7), Differential 0.127 vs 0.097(p=4.9*10^-3), BMP 0.862 vs 0.805(p=0.022), LFT 0.174 vs 0.153(p=0.12), Mg 0.483 vs 0.364(p=3.6*10^-7), Ph 0.289 vs 0.213(p=4.0*10^-5). Similarly, comparing the 3 intervention team lab ordering habits for 3 months to themselves 3 months prior to the intervention showed a reduction of CBCs 0.792 vs 0.580, Differential 0.121 vs 0.097, BMP 0.900 vs 0.805 and Ph 0.272 vs 0.213. LFTs and Mg did not achieve a difference with statistical significance (P>0.05). Comparing average daily labs ordered for control vs intervention over five months however showed a statistically significant difference only for CBCs, with control 0.657 vs intervention 0.610(P=0.03) with a trend showing future narrowing of the difference further. Phosphorus ordering conversely increased with 0.240 control vs 0.284 intervention, P=0.01.


Regular audit and feedback with peer comparison on lab ordering may reduce number of labs ordered over time on a general medicine service as seen with statistical significance in the first three months of intervention above. The effect however may be time-limited as evidenced by the fact that the reduction did not persist over a longer period.

Clinical Implications

If sustainability of results can be achieved, the intervention may lower costs of care and discomfort to patients from venipuncture.

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