Free tool · Scored assessment · ER / VTE
Wells & PERC — DVT / PE Risk.
Three bedside VTE tools in one place. Wells for DVT and Wells for PE give a pretest-probability score; the PERC rule helps decide whether a low-risk patient can have PE excluded without further testing. Pick a tool, check what applies, and get the score, the probability band, and the usual next step. Built from Wells and Kline (PERC). These scores support the workup — the provider orders and interprets testing.
Wells criteria — DVT
Check each finding that is present.
Check the findings that apply, then interpret.
About these tools [1][2][3]
Wells DVT (each +1; alternative diagnosis as likely −2): three-tier — ≤0 low, 1–2 moderate, ≥3 high; two-tier — ≥2 “DVT likely”, <2 “unlikely.” Wells PE (weighted): three-tier — <2 low, 2–6 moderate, >6 high; two-tier — ≤4 “PE unlikely”, >4 “likely.” A D-dimer is commonly used to exclude VTE in the unlikely/low groups. PERC applies only when clinical gestalt for PE is already low; if all 8 criteria are satisfied, the risk of PE is low enough that no further testing (including D-dimer) is generally needed. If any PERC item fails, PERC cannot exclude PE — proceed with risk-appropriate testing.
References
- Wells PS, Anderson DR, Bormanis J, et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. Lancet. 1997;350(9094):1795–1798. PMID: 9428249; Wells PS, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. 2003;349:1227–1235.
- Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thromb Haemost. 2000;83(3):416–420. PMID: 10744147; Christopher Study (two-tier Wells + D-dimer). JAMA. 2006;295:172–179.
- Kline JA, Mitchell AM, Kabrhel C, Richman PB, Courtney DM. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism (PERC). J Thromb Haemost. 2004;2(8):1247–1255. PMID: 15304025; multicenter validation. J Thromb Haemost. 2008;6:772–780.
Criteria and probability bands transcribed from the cited studies. Testing decisions are made by the provider.
Pairs well with