At this very early stage in the diagnostic pathway, acute stroke is still 'suspected'; the CT may show up an alternative diagnosis or further clinical assessment may also reveal an alternative diagnosis (the CT is often performed directly off the ambulance when there is little more than 'FAST +ve' criteria). CT angiography and CT perfusion indications have been added to be consistent with the new recommendations on thrombectomy. 2022 Recommendation 1.4.2 has been amended to clarify that the levels relate to the level of care required by the patient. Recommendation 1.5.7 has been amended to be consistent with the subheading for this recommendation, which now applies to acute ischaemic stroke (that is, not haemorrhagic stroke). The remaining part of the recommendation has been replaced by recommendation 1.5.5. These recommendations are marked [2008, amended 2019]. Recommendations marked [2008] last had an evidence review in 2008. In some cases, minor changes have been made to the wording to bring the language and style up to date, without changing the meaning. Minor changes since publication March 2023: We have corrected the link in recommendation 1.2.4. October 2022: We added text to indicate that pulse oximetry may be less reliable in people with dark skin. We also added a link to the NHS patient safety alerton the risk of harm from inappropriate placement of pulse oximeter probes. See recommendation 1.5.1. November 2021: We added a link to the NHS England and NHS Improvement National Stroke Service Model in section 1.3 on specialist care for people with acute stroke. October 2020: We added the research recommendations from the 2008 guideline. April 2020: We corrected the links to the rationales in section 1.1 on rapid recognition of symptoms and diagnosis. 2022 Accreditation 2022