Covid 19 Rapid Lateral Flow Test

Overview

A rapid lateral flow test is a quick test you can do at home to check whether you have COVID-19. You wipe a soft swab around your nose (and sometimes the back of your throat), mix it with a liquid, and drip the liquid onto a small test strip. The strip shows coloured lines that tell you the result, usually within 15 to 30 minutes. It is called 'lateral flow' because the liquid flows sideways along the strip. The test looks for small pieces of the virus, called antigens, which your body's immune system would react to.

Yes. Rapid lateral flow tests have been used on a very large scale around the world — in people's homes, schools, workplaces, care homes and hospitals — because they are cheap, quick and easy to use without special equipment.

Anyone can use one. They are used by people with no symptoms to check whether they might be infectious, and by people with symptoms. Some people find swabbing uncomfortable, and young children usually need an adult to help. People with a weakened immune system, older adults and pregnant women may be advised to take extra care about their results and to seek advice early.

Symptoms

Common symptoms

• A high temperature or feeling hot, cold or shivery
• A new, continuous cough
• A loss or change in your sense of smell or taste
• Tiredness or aching muscles
• A sore throat, headache or blocked or runny nose
• Feeling sick, having diarrhoea, or losing your appetite

Symptoms in children

• Children often have mild symptoms that look like a common cold
• A high temperature, sore throat or cough
• Tummy upset, vomiting or diarrhoea can be more common in children than in adults
• Some children have no symptoms at all and are only found through testing
• A rash, or unusual tiredness, is sometimes reported

Symptoms in older adults

• Symptoms can be less typical — for example confusion, being more unsteady, or a fall
• Worsening of an existing health problem, such as breathlessness in a lung or heart condition
• A high temperature may be absent, or the person may simply seem 'not themselves'
• Reduced appetite, drowsiness or dehydration
• Breathlessness or a drop in oxygen levels, which can be picked up with a home oxygen monitor if your health service has provided one

Causes

Main causes

• The test does not cause illness — it detects infection with the virus that causes COVID-19 (SARS-CoV-2)
• A positive result means virus particles were found in your sample, which usually means you are infected and may be able to pass the virus to others
• A negative result can happen if you test very early or very late in an infection, if you did not swab thoroughly, or if the test was stored or used incorrectly

Risk factors

• Close contact with someone who has COVID-19
• Crowded or poorly ventilated indoor spaces
• Not being up to date with recommended vaccinations
• A weakened immune system, which can make infection more serious and can also affect test results
• Working or living in a setting where the virus spreads easily, such as a care home or hospital ward

When to see a doctor

See a doctor urgently if:

• You have a positive test and you are at higher risk of serious illness — for example a weakened immune system, pregnancy, or an older age — ask your doctor or local health service the same day about whether assessment or treatment is right for you
• You feel very breathless, faint, dehydrated or much worse than expected
• You are caring for someone whose symptoms are worsening quickly

Book a routine appointment if:

• You are unsure what your result means, or the lines are unclear or appeared after the reading time
• You have symptoms that are not settling after a few weeks
• You need advice about work, school, travel or caring responsibilities
• You have a long-term condition and want to know how to manage it during infection

Diagnosis

The lateral flow test itself is the test. You follow the kit instructions: swab the inside of your nose (some kits also ask for the back of the throat), stir the swab in a small tube of liquid, then squeeze a few drops onto the test strip. You wait the time stated on the instructions — usually 15 to 30 minutes — and then read the lines. Do not read the result after the stated time, as it may be wrong.

Tests that may be done

• Rapid lateral flow test (antigen test) — quick, done at home, results in minutes
• Polymerase chain reaction (PCR) test — a laboratory test that is more sensitive and can pick up smaller amounts of virus; in many places it is no longer needed to confirm a positive lateral flow result, so check your local guidance
• Repeat lateral flow testing — for example testing on several days in a row, which improves the chance of catching an infection
• A home oxygen monitor (pulse oximeter) may be provided to some higher-risk people to check oxygen levels at home

What to expect at your appointment

Swabbing can tickle, make your eyes water or make you sneeze, but it is over in seconds. The wait for the result is short. A positive result can feel worrying — take a moment, then follow your local guidance about staying away from others and tell anyone you have been in close contact with. A negative result is good news but not a guarantee, so if you still have symptoms, keep away from others until you feel better and consider testing again.

Treatment

There is no cure that clears the virus quickly, so treatment focuses on easing symptoms, resting and watching for signs of worsening illness. Most people recover fully at home without any medical treatment.

Self-care at home

• Rest and drink plenty of fluids to avoid dehydration
• Take simple over-the-counter remedies for fever or aches if you need them — ask your pharmacist which are suitable for you, especially if you take other medicines, are pregnant or are breastfeeding
• Stay away from other people while you are likely to be infectious, following the guidance where you live
• Open windows and ventilate rooms if you must share a space with others
• Check your symptoms regularly, and ask someone to check on you if you live alone
• Return to normal activity gradually — build up slowly if you feel tired

Medical treatments

Most people do not need medical treatment. If you are at higher risk of serious illness, your doctor may assess you and discuss whether treatments offered by your local health service are appropriate — these are usually most effective when given early, so contact them promptly after a positive test rather than waiting. For people who become seriously unwell, hospital care can include oxygen support and close monitoring. Your healthcare team will explain any options that apply to your own situation.

When is surgery considered?

Surgery is not relevant to this test or to COVID-19 infection.

Living with this condition

Plan for a few quiet days. Keep medicines you might need within reach, keep water by your bed, and let someone know you are unwell so they can check in. Keep a note of your temperature and how you feel, and follow the isolation or distancing guidance where you live. Wash your hands often and use your own towel and cup if you share a home.

Lifestyle tips

• Ventilate rooms by opening windows, even briefly
• Wash hands regularly with soap and water, or use hand gel
• Cover coughs and sneezes, and clean frequently touched surfaces
• Avoid visiting people who are vulnerable while you may be infectious
• Keep up to date with recommended vaccinations when you are well

Diet and exercise

Eat regularly and drink more than usual, especially if you have a fever — soups, toast and fruit are fine if your appetite is low. Rest is more important than exercise while you are unwell. Once you feel better, start with short walks and gentle activity and build up over days or weeks. If you feel breathless or exhausted afterwards, ease off and try again later.

Mental health and emotional wellbeing

Being unwell and staying away from others can feel lonely and stressful, and it is normal to feel anxious about your result or about passing the virus on. Keep in contact with friends and family by phone or video, keep to a simple daily routine, and be kind to yourself. If you feel persistently low, anxious or unable to cope, tell your doctor — support is available. If you ever feel you cannot keep yourself safe, contact your local emergency number or a crisis line in your country straight away.

Prevention

You can reduce the spread of COVID-19 with simple steps: staying away from others when unwell, ventilating indoor spaces, washing hands often, and keeping up to date with recommended vaccinations. Lateral flow testing itself does not prevent infection, but it helps you find out you are infectious so you can avoid passing the virus on.

Vaccines

Vaccinations against COVID-19 are offered by local health services around the world. They are very good at reducing the risk of serious illness, though they do not stop every infection. Who is offered a vaccine, and how often, changes over time and varies by country — ask your doctor, nurse or pharmacist what applies to you.

Screening programmes

Regular lateral flow testing is a form of screening: it can find infection in people who have no symptoms, so they can avoid spreading the virus. Some workplaces, care homes and hospitals use regular testing in this way. Follow the guidance from your local health service about when and how often to test.

Complications

If left untreated

• The virus can spread to family, friends, colleagues and anyone you meet, including people who are vulnerable
• Some people develop longer-lasting symptoms often called 'long COVID' — tiredness, breathlessness, brain fog or a racing heart lasting weeks or months
• A small number of people become seriously unwell with breathing difficulties and need hospital care
• Existing health conditions can become harder to manage during infection
• Rarely, other complications can occur, such as blood clots or inflammation of the heart or lungs

Long-term outlook

The great majority of people recover from COVID-19 within a few days to a few weeks and get back to normal life. Testing early helps you protect others and get advice quickly if you are at higher risk. If symptoms drag on, support and rehabilitation are available — speak to your doctor, and try to be patient with your recovery.

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