3 Investigations and referral

3 Investigations and referral

These recommendations are for healthcare professionals carrying out initial investigations in primary care or community services for people with new or ongoing symptoms 4 weeks or more after the start of suspected or confirmed acute COVID-19. See the NICE guideline on shared decision making for advice on how to make appropriate investigations and referrals.


Offer tests and investigations tailored to people's signs and symptoms to rule out acute or life‑threatening complications and find out if symptoms are likely to be caused by ongoing symptomatic COVID‑19, post‑COVID‑19 syndrome or could be a new, unrelated diagnosis. [2020]


Refer people with ongoing symptomatic COVID-19 or suspected post-COVID-19 syndrome urgently to the relevant acute services if they have signs or symptoms that could be caused by an acute or life‑threatening complication, including (but not limited to):

  • hypoxaemia or oxygen desaturation on exercise

  • signs of severe lung disease

  • cardiac chest pain

  • paediatric inflammatory multisystem syndrome – temporally associated with SARS-CoV-2 (PIMS-TS). [2020]


If another diagnosis unrelated to COVID-19 is suspected, offer investigations and referral in line with relevant national or local guidance. [2020]


Decisions about blood tests should be guided by the person's symptoms. If clinically indicated, offer blood tests, which may include a full blood count, kidney and liver function tests, C‑reactive protein, ferritin, B‑type natriuretic peptide (BNP), HbA1c and thyroid function tests. [2020, amended 2021]


Consider supported self-monitoring at home, if this is agreed through shared decision making as part of the person's assessment. This may include heart rate, blood pressure, pulse oximetry or symptom diaries. Ensure that people have clear instructions on how to use any equipment and parameters for when to seek further help.

Be aware that some pulse oximeters can underestimate or overestimate oxygen saturation levels, especially if the saturation level is borderline. Overestimation has been reported in people with dark skin. For more information about this, see NHS England's guide on how to look after yourself at home if you have COVID-19 or symptoms of COVID-19. [2020, amended 2021]


If appropriate, offer an exercise tolerance test suited to the person's ability (for example, the 1‑minute sit‑to‑stand test). During the exercise test, record level of breathlessness, heart rate and oxygen saturation. Follow an appropriate protocol to carry out the test safely (see the rationale section for suggested protocols).

Sharing skills between services can help community services to manage these assessments; for advice, see recommendation 8.3 on sharing skills and training in the section on service organisation. [2020]


For people with postural symptoms, for example, palpitations or dizziness on standing, carry out lying and standing blood pressure and heart rate recordings (3‑minute active stand test for orthostatic hypotension, or 10 minutes if you suspect postural tachycardia syndrome, or other forms of orthostatic intolerance). [2020]


Offer a chest X-ray by 12 weeks after acute COVID-19 only if the person has continuing respiratory symptoms and it is clinically indicated. Chest X‑ray appearances alone should not determine the need for referral for further care.

Be aware that a normal plain chest X-ray does not rule out lung disease. [2020, amended 2021]


Refer people with ongoing symptomatic COVID-19 or suspected post‑COVID‑19 syndrome urgently for psychiatric assessment if they have severe psychiatric symptoms or are displaying high risk of self‑harm or suicide. [2020]


Follow relevant national or local guidelines on referral for people who have anxiety and mood disorders or other psychiatric symptoms. Consider referral:

  • for psychological therapies if they have common mental health symptoms, such as symptoms of mild anxiety and mild depression or

  • to a liaison psychiatry service if they have more complex needs (especially if they have a complex physical and mental health presentation). [2020]


After ruling out acute or life-threatening complications and alternative diagnoses, consider referring people to an appropriate service, such as an integrated multidisciplinary assessment service, any time from 4 weeks after the start of acute COVID‑19.

Many people experience a spontaneous improvement in symptoms between 4 and 12 weeks after the start of acute COVID‑19 and should be offered self-management support and monitoring during this time, with consideration of onward referral to further services if they do not improve. People with concerning symptoms during this time may need referral for assessment by acute medical services. [2020, amended 2021]


Do not exclude people from referral to an integrated multidisciplinary assessment service or for further investigations or specialist input based on the absence of a positive SARS‑CoV‑2 test (PCR, antigen or antibody) as long as the case definition criteria are met. [2020, amended 2021]

For a short explanation of why the panel made these recommendations, see the rationale section on investigations and referral.

Full details of the evidence and the panel's discussion are: