KEY POINTS: Pay-for-performance indicators and lack of knowledge about new drugs limit general practitioners' ability to identify target populations and perform urinary protein assays. Choosing between several possible assays is associated with confusion and exposes general practitioners to the risk of inappropriate referrals to nephrologists. Revising pay-for-performance indicators, drafting multidisciplinary guidelines, raising multiprofessional collaboration, and patient awareness should be considered. BACKGROUND: Albuminuria testing is an easy way to identify, early on, a higher risk of cardiovascular and kidney morbidity and mortality in patients at risk. In France, the urine albumin-to-creatinine ratio is an indicator for Remuneration for Public Health Objectives (primary care pay-for-performance) for patients with diabetes or hypertension. These tests must be performed annually by General Practitioners (GPs), but are not sufficiently performed, although drug therapies depend on them. We wanted to understand the practice of urinary protein screening assays by means of a qualitative study on the experience of GPs in a French region, with a view to developing facilitating strategies. METHODS: This qualitative, semiopragmatic, phenomenological study analyzed in-depth interviews held with a purposive sample (age, sex, training, type of practice, rural/urban context) of 27 GPs, with triangulation of researchers until data saturation. RESULTS: GPs recognized the assay as a systematic screening tool in accordance with the guidelines, but limited it to patients with diabetes or hypertension encouraged by primary care pay-for-performance. Noting that their intervention was limited to kidney-protective measures already in place and, unaware of the new drugs, they saw no benefits and considered it a nonpriority test. The existence of several urinary assays with varying intervention thresholds, changes in guidelines, and the fact that specialists in laboratory medicine can decide which test to use depending on reimbursement by the health insurance scheme, all contributed to GPs' confusion in prescribing and interpreting tests. One consequence of this was inappropriate referral to the nephrologist. These tests required them to adopt a patient-centered educational approach, making it difficult for certain patients to perform them. CONCLUSIONS: GPs were aware of guideline recommendations to screen for albuminuria in patients with diabetes and hypertension but had difficulty interpreting the results. Their lack of perceived clinical consequences and new drugs should be targeted to improve the situation.