We describe a potentially cost-saving, efficient alternative to hospitalising patients for diagnostic purposes: quick diagnosis units (QDUs) managed by internal medicine specialists.

QDUs facilitate early diagnosis for patients with potentially serious disease, and avoid hospitalisations, hospital-related morbidity and unnecessary health costs.

To function well, QDUs require the patient’s first visit to occur as soon as possible after referral; preferential patient access to diagnostic tests; and strict referral criteria (QDU patients must have symptoms suggestive of severe disease, but be well enough to attend several appointments for diagnostic tests).

We describe the experience of two Spanish QDUs in which the most frequent diagnosis was malignant neoplasm.

We conclude that QDUs are an effective alternative to conventional hospitalisation, reducing delays in diagnosing potentially severe disease, such as cancer. They reduce costs without lowering the quality of diagnostic practice or patient care, and free acute-care beds for patients in need of treatment.