Karen is 35 years old and is 20 weeks pregnant. She is concerned her right calf is swollen and painful since yesterday despite no obvious injury to it. She has no other past medical history and is just taking Folic acid. She has been keeping active and has no recent surgery or travel history. On examination her right calf measures 41cm and left calf measures 37cm. The right calf is tender to touch along the deep venous system and there are no collateral veins or pitting oedema.
What is her Wells score?