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Flowflex Antigen Rapid Test Lateral Flow Self-Testing

Flowflex Antigen Rapid Test Lateral Flow Self-Testing

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  • ✔️ Detects SARS-CoV-2 antigens from a simple nasal swab
  • ✔️ Delivers a clear positive or negative result in 15 minutes
  • ✔️ Suitable for adults and children aged 2 and over
  • ✔️ CE-marked for reliable at-home COVID-19 self-testing
  • ✔️ No prescription required — test confidently at home

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What Is a Lateral Flow Test and How Does It Detect COVID-19?

 

If you've ever wondered whether that scratchy throat is just a cold or something more, a lateral flow test gives you a clear answer in under 15 minutes — right from your own home. The Flowflex Antigen Rapid Test is a single-use, CE-marked self-test designed to detect SARS-CoV-2 antigens from a simple nasal swab. At just £4.99, it's one of the most accessible ways to check your COVID-19 status quickly and confidently. Whether you're heading to visit a vulnerable relative or you've woken up feeling under the weather, having a test to hand makes a real difference.

Rapid antigen testing became a cornerstone of the UK's COVID-19 response, and the NHS continues to recommend testing when symptoms are present or before contact with people at higher risk. The Flowflex test is suitable for home use by adults and children aged 2 and over, with no healthcare professional required. If you're also managing other health concerns, you might find our cold and flu range useful alongside your testing kit.

 

How Does the Flowflex Antigen Rapid Test Work?

 

The science behind this test is straightforward, even if the name sounds technical. It uses immunochromatographic technology — essentially, antibodies fixed to a membrane that bind specifically to SARS-CoV-2 nucleocapsid proteins (antigens) if they're present in your sample.

  • You collect a nasal swab sample from both nostrils.
  • The swab is mixed into an extraction buffer solution.
  • Three drops of the solution are applied to the test cassette.
  • The liquid migrates along the test strip, and if viral antigens are present, they bind to labelled antibodies, producing a visible coloured line at the T (test) position.
  • A control line (C) always appears if the test has worked correctly.
  • Results are read at exactly 15 minutes — not before, not after.

One line (C only) means a negative result. Two lines (C and T) — even a faint T line — means a positive result. No C line at all means the test is invalid and should be repeated.

 

Who Should Use the Flowflex Antigen Rapid Test?

 

This test is designed for anyone who wants a fast, convenient way to check for COVID-19 at home. It's particularly useful if you develop symptoms such as a new continuous cough, high temperature, or a loss or change to your sense of smell or taste — the three main symptoms highlighted by the NHS. It's also sensible to test before visiting elderly relatives, attending crowded indoor events, or returning to work after illness.

  • Adults experiencing COVID-19 symptoms
  • People who have been in close contact with a confirmed case
  • Carers or healthcare workers wanting to reduce transmission risk
  • Children aged 2 and over (with adult supervision)

 

How Does the Flowflex Test Compare to a PCR Test?

 

Feature Flowflex Lateral Flow Test PCR Test
Result time 15 minutes 24–72 hours
Location At home Laboratory
Detects Viral antigens Viral RNA (genetic material)
Sensitivity High (best when symptomatic) Very high
Cost £4.99 Varies (often £50–£120 privately)
Prescription needed No No (but lab referral needed)

 

How Should You Store the Flowflex Antigen Rapid Test?

 

Proper storage is essential to ensure your lateral flow test gives you a reliable result when you need it most. Keep the sealed pouch at room temperature — below 30°C — in a dry location away from direct sunlight. Do not freeze the kit, as this can damage the reagents and invalidate the test. Once opened, the test must be used immediately.

Check the expiry date printed on the outer packaging before use. An expired test may not perform correctly. If you're building a home health kit, our first aid collection has everything else you might need alongside your testing supplies.

This product is a medical device. Speak to your doctor or pharmacist before using if you have an underlying medical condition or are taking other medicines.

Flowflex Antigen Rapid Test Lateral Flow Self-Testing specifications
Treatment category Diagnostic / COVID-19 self-testing
Mechanism of action Immunochromatographic antigen detection
Effective against SARS-CoV-2 (COVID-19)
Suitable for Adults and children aged 2 and over
Active ingredient Anti-SARS-CoV-2 antibody-coated membrane
Pack sizes 1 test per pack
UK classification CE-marked medical device (IVD)
Preparation Nasal swab with extraction buffer
Route of administration Nasal swab (self-collected)
Result time 15 minutes

Specifications of Flowflex Antigen Rapid Test Lateral Flow Self-Testing

 

What Is the Flowflex Antigen Rapid Test and What Is It Used For?

 

The Flowflex Antigen Rapid Test is a single-use, in vitro diagnostic (IVD) medical device intended for the qualitative detection of SARS-CoV-2 nucleocapsid antigens in nasal swab samples. In plain English: it tells you whether the COVID-19 virus is currently active in your body. It is not a test for past infection or immunity — it detects the virus itself, not antibodies.

This test is intended for self-use at home by adults and supervised use in children aged 2 and over. It is most accurate when used within the first five days of symptom onset, when viral load tends to be highest. The NHS advises testing if you have symptoms consistent with COVID-19, or if you've been in close contact with someone who has tested positive.

 

What Do You Need to Know Before Using the Flowflex Antigen Rapid Test?

 

Before you open the kit, there are a few important things to be aware of. This test is for nasal use only — do not attempt to use it orally or in any other way not described in the instructions.

Do not use this test if:

  • The sealed foil pouch is damaged or has been previously opened
  • The test has passed its expiry date
  • You have had nasal surgery in the past four weeks
  • You have a known severe allergy to any component of the test kit
  • The child being tested is under 2 years of age

Important warnings:

  • A negative result does not completely rule out SARS-CoV-2 infection — if symptoms persist, seek further medical advice
  • This test is not a substitute for laboratory PCR testing in clinical settings
  • Results should be interpreted alongside clinical symptoms and exposure history
  • The extraction buffer contains sodium azide — avoid contact with skin and eyes; dispose of safely
  • All used test components should be treated as potentially infectious and disposed of in household waste (not recycling)

Drug interactions:

  • No known drug interactions — this is a diagnostic device, not a medicine
  • Certain nasal sprays or decongestants used immediately before testing may theoretically affect sample quality; blow your nose gently and wait 30 minutes before swabbing if possible

 

How Should You Use the Flowflex Antigen Rapid Test?

 

Read the full instructions inside the pack before you begin. Wash your hands thoroughly with soap and water for at least 20 seconds before handling any components. Lay all items out on a clean, flat surface.

  1. Open the foil pouch and remove the test cassette, swab, and extraction tube.
  2. Peel the label from the extraction tube and stand it upright in the tube holder.
  3. Gently insert the swab approximately 2 cm into one nostril and rotate it five times against the nasal wall.
  4. Repeat in the other nostril using the same swab.
  5. Insert the swab into the extraction buffer in the tube and stir vigorously for 30 seconds.
  6. Squeeze the tube sides while removing the swab to retain as much liquid as possible; discard the swab safely.
  7. Attach the dropper tip to the tube.
  8. Hold the tube vertically and apply exactly 3 drops to the sample well (S) on the test cassette.
  9. Wait exactly 15 minutes before reading the result — do not read after 20 minutes.
User Age Group Swab Depth Supervision Required
Adult (self-test) 18 and over ~2 cm into each nostril No
Older child 12–17 ~2 cm into each nostril Recommended
Young child 2–11 ~1–1.5 cm (shallower) Yes — adult must perform
Infant Under 2 Not recommended Seek medical advice

 

What Are the Possible Side Effects of the Flowflex Antigen Rapid Test?

 

As a diagnostic device rather than a medicine, the Flowflex test does not cause systemic side effects. However, some people do experience minor discomfort during or after use. If you're feeling unwell and testing alongside other treatments, our pain relief range may help manage symptoms while you await your result.

Common experiences:

  • Mild nasal discomfort or tickling sensation during swabbing
  • Temporary watering of the eyes triggered by nasal stimulation
  • Sneezing during or immediately after swabbing

Less common experiences:

  • Minor nasal bleeding (epistaxis) — particularly in people with sensitive nasal passages or those on anticoagulant medicines
  • Anxiety or distress related to the testing process, especially in children
  • Skin irritation if the extraction buffer contacts the skin — rinse with water if this occurs

If nasal bleeding does not stop within 10 minutes, or if you experience any unexpected reaction, seek medical advice promptly.

 

How Should You Store the Flowflex Antigen Rapid Test?

 

Correct storage protects the integrity of the test components and ensures you get a reliable result. If you're building a home health kit, consider pairing your tests with products from our electrical health and diagnostic collection for a more complete monitoring setup.

  • Store in the original sealed foil pouch until ready to use
  • Keep at room temperature: 2°C to 30°C
  • Do not freeze — freezing damages the antibody-coated membrane
  • Keep away from direct sunlight and sources of heat or moisture
  • Store out of reach of children
  • Do not use after the expiry date printed on the outer carton
  • Once opened, use immediately — do not reseal and store for later use

Written and reviewed by our qualified team

Your safety and success are our highest priorities. Our medical team rigorously evaluates every product and piece of advice we provide, ensuring you receive only the most effective, science-backed solutions available.

Frequently Asked Questions

Where can I buy the Flowflex lateral flow test online in the UK?

You can buy the Flowflex Antigen Rapid Test directly from Cured Pharmacy online for £4.99 per test with no prescription required. It's dispatched quickly to your home address, so you don't need to visit a pharmacy in person. Simply add it to your basket and check out in minutes.

How does the Flowflex antigen rapid test work in the body?

The test uses immunochromatographic technology to detect SARS-CoV-2 nucleocapsid antigens present in your nasal secretions. Antibodies fixed to the test strip bind to viral proteins if they are present in your sample, producing a visible coloured line. It does not detect antibodies or past immunity — only active viral antigens at the time of testing.

How do I use the Flowflex lateral flow test step by step?

Wash your hands, then insert the swab approximately 2 cm into each nostril and rotate five times per nostril. Place the swab into the extraction buffer tube, stir for 30 seconds, then apply 3 drops to the test cassette sample well. Read your result at exactly 15 minutes — one line is negative, two lines (even faint) is positive.

When is the best time to use a lateral flow test for COVID-19?

The NHS recommends testing as soon as you develop symptoms such as a new cough, high temperature, or loss of smell or taste. Testing in the morning before eating, drinking, or using nasal sprays may help improve sample quality. Antigen tests are most sensitive within the first five days of symptom onset when viral load is typically highest.

What does a faint line on the Flowflex test mean?

Any visible line in the T (test) position — however faint — is considered a positive result and should be treated as such. The intensity of the line does not indicate how infectious you are or how severe your illness will be. You should follow current NHS guidance and consider avoiding contact with vulnerable individuals.

Can children use the Flowflex antigen rapid test?

Yes, the Flowflex test can be used in children aged 2 and over, but an adult must perform or closely supervise the test for younger children. For children aged 2 to 11, insert the swab slightly less deeply — around 1 to 1.5 cm — to avoid discomfort. Children under 2 should not be tested with this kit; seek medical advice instead.

How accurate is the Flowflex antigen rapid test?

The Flowflex test has demonstrated high sensitivity and specificity in clinical evaluations for detecting SARS-CoV-2 antigens, particularly when used during the symptomatic phase of infection. However, no rapid antigen test achieves 100% accuracy, and false negatives can occur — especially early in infection or when viral load is low. If you have strong symptoms but a negative result, consider retesting after 24 hours or seeking a PCR test.

What should I do if my Flowflex test result is positive?

If your result is positive, the NHS advises trying to stay at home and avoiding contact with people who are at higher risk of serious illness, particularly in the first five days. You do not currently need to legally self-isolate in England, but it is strongly recommended to protect others. Inform anyone you've had close contact with recently so they can consider testing themselves.

What happens if the control line does not appear on the Flowflex test?

If no control line (C) appears, the test is invalid and the result cannot be trusted regardless of whether a T line is visible. This can happen if insufficient sample was applied, the test was not performed correctly, or the kit was damaged. Discard the test and repeat with a new kit, following the instructions carefully.

Who is eligible to use the Flowflex lateral flow test?

The test is suitable for adults and children aged 2 and over who want to check for active COVID-19 infection at home. It is particularly recommended for people with symptoms, those who have been in close contact with a confirmed case, and carers or healthcare workers wanting to reduce transmission risk. People with recent nasal surgery should seek medical advice before using a nasal swab test.

What are the alternatives to the Flowflex lateral flow test?

The main alternative is a PCR (polymerase chain reaction) test, which detects viral RNA rather than antigens and is more sensitive — but results take 24 to 72 hours and are usually processed in a laboratory. Other CE-marked lateral flow antigen tests from different manufacturers are also available from pharmacies. If you're managing ongoing health monitoring at home, our electrical health and diagnostic range includes additional monitoring tools.

Can I use the Flowflex test if I have no symptoms?

Yes, you can use the test asymptomatically — for example, before visiting someone who is elderly or immunocompromised, or before attending a large indoor gathering. However, antigen tests are generally less sensitive in asymptomatic individuals because viral load may be lower. A negative result in an asymptomatic person should be interpreted with caution.

How long does the Flowflex test take to give a result?

You should read your result at exactly 15 minutes after applying the sample drops to the cassette — not before and not after 20 minutes. Reading the result outside this window can lead to inaccurate interpretation, as evaporation lines may appear after 20 minutes that could be mistaken for a positive result. Set a timer as soon as you apply the drops.

What are the latest studies on lateral flow antigen tests for COVID-19?

Published data from the UK Health Security Agency (UKHSA) and peer-reviewed studies have consistently shown that lateral flow antigen tests perform best during the symptomatic phase of COVID-19, with sensitivity typically ranging from 72% to 97% depending on the test brand and timing. Specificity (the ability to correctly identify a negative result) is generally very high, above 99%, meaning false positives are rare. Ongoing surveillance data continues to support their use as a practical tool for rapid community testing.

How should I dispose of the Flowflex test after use?

All used components — including the swab, extraction tube, and test cassette — should be treated as potentially infectious clinical waste and placed in a sealed plastic bag before disposal in your household general waste bin. Do not place used test components in recycling. If you tested positive, take extra care to minimise handling of used materials and wash your hands thoroughly after disposal. You can find further guidance on safe disposal from the NHS website.

How Should You Use the Flowflex Antigen Rapid Test?

Before you begin, wash your hands thoroughly with soap and water for at least 20 seconds. Lay all components out on a clean, flat surface and check that the foil pouch is intact and the expiry date has not passed.

What Is the Correct Dose of the Flowflex Antigen Rapid Test?

This is a single-use diagnostic device, not a medicine, so "dose" refers to the number of drops applied and the frequency of testing. Each test kit contains one cassette and should only be used once. If you need to retest — for example, after an invalid result or to confirm a negative during ongoing symptoms — use a new kit each time.

When Is the Best Time to Use the Flowflex Antigen Rapid Test?

Antigen tests are most sensitive during the first five days of symptom onset, when viral load is typically at its highest. Testing in the morning before eating, drinking, or using nasal sprays is generally recommended to avoid any potential interference with the nasal sample. If you are testing asymptomatically before visiting a vulnerable person, test as close to the visit as practically possible — ideally within a few hours.

Avoid blowing your nose vigorously immediately before swabbing, as this may reduce the amount of viral material on the nasal mucosa. If you have recently used a nasal decongestant spray, wait at least 30 minutes before collecting your sample.

How Long Can You Use the Flowflex Antigen Rapid Test For?

Each Flowflex kit is a single-use device and cannot be reused. There is no ongoing treatment course — you simply test as and when clinically appropriate. If you test negative but symptoms continue or worsen after 24 to 48 hours, the NHS recommends retesting with a fresh kit or seeking a PCR test for greater sensitivity.

Store unused kits in their sealed foil pouches below 30°C until the printed expiry date. There is no limit on how many times you can test over a period, provided you use a new kit each time and follow the instructions correctly.

Do not exceed the recommended dose. If in doubt, speak to your pharmacist.

What Are the Most Common Side Effects of the Flowflex Antigen Rapid Test?

Because this is a diagnostic device rather than a medicine, it does not cause systemic side effects. The most commonly reported experiences relate to the physical process of nasal swabbing rather than any chemical reaction in the body.

  • Mild nasal discomfort or tickling sensation during swab insertion
  • Temporary watering of the eyes triggered by nasal stimulation
  • Sneezing during or immediately after swabbing
  • Brief stinging sensation if the nasal passages are already inflamed

What Are the Less Common Side Effects of the Flowflex Antigen Rapid Test?

Less commonly, some people experience slightly more noticeable reactions, particularly if they have sensitive nasal passages or are taking medicines that affect bleeding. These are generally mild and short-lived.

  • Minor nasal bleeding (epistaxis) — more likely in people on anticoagulants such as warfarin or aspirin, or those with fragile nasal mucosa
  • Skin irritation if the extraction buffer solution contacts the skin — rinse the affected area with clean water for several minutes if this occurs
  • Eye irritation if the buffer contacts the eyes — rinse immediately with clean water and seek medical advice if irritation persists
  • Anxiety or distress in children related to the swabbing process

What Are the Serious Side Effects of the Flowflex Antigen Rapid Test?

Serious adverse reactions to lateral flow nasal swab tests are extremely rare. However, you should seek prompt medical attention if you experience any of the following after using this test.

  • Nasal bleeding that does not stop within 10 minutes of applying gentle pressure
  • Signs of an allergic reaction such as swelling of the face, lips, or throat, difficulty breathing, or a widespread skin rash
  • Significant pain or injury to the nasal passage — this should not occur with correct technique but may happen if the swab is inserted too forcefully

What Should You Do If You Experience Side Effects?

For minor nasal discomfort or sneezing, no action is needed — these sensations pass within a few minutes. If you experience nasal bleeding, tilt your head slightly forward (not back), pinch the soft part of your nose, and hold for 10 minutes. Do not tilt your head backwards, as this can cause blood to flow into the throat.

If you suspect an allergic reaction to any component of the test kit, stop use immediately and seek urgent medical attention. Contact NHS 111 or your GP if you are unsure whether your symptoms require assessment. Keep the test packaging so that healthcare professionals can identify the components involved.

Can the Flowflex Antigen Rapid Test Interact With Other Medicines?

As a diagnostic device, the Flowflex test does not interact with medicines in the way that drugs do. However, certain nasal preparations — including corticosteroid nasal sprays, decongestant sprays, and saline rinses — may theoretically affect the quality of your nasal sample if used immediately before testing. It is advisable to wait at least 30 minutes after using any nasal preparation before collecting your swab sample. If you are taking anticoagulant medicines, be particularly gentle during swabbing to minimise the risk of minor nasal bleeding.

If you are concerned about any side effects, contact your pharmacist or GP immediately.

Patient Information Leaflet

Important - Before taking any medication, it is always important to read the Patient Information Leaflet (PIL)

Written and reviewed by our qualified team

GPhC Number: 2233073
Tarun Kumar

Reviewed by:

Tarun Kumar

Superintendent/ Clinical Lead

📖 Find out more about our team of medical content authors and how we ensure the accuracy of our content with our content guidelines.

Content last updated: 31 Mar 2025

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