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Why did only one out of the eight lateral flow COVID tests show positive?

This Premium Q&A, reviewed and published, features a real conversation between an iCliniq user and a physician.

Patient's Query

Hi doctor,

I carried out lateral flow tests regularly for COVID-19. Over the last few weeks, my family has stayed at home for the holidays. Yesterday morning I did a positive test.

I have since then tested myself 8 times, and all have been negative. I have no symptoms. I think the first test was a false positive, as I had carried it out directly after eating buttered toast. As the lateral flow picks up proteins and fatty acids, the butter has activated it.

There were crumbs on the swab on the first test. Have you heard of this triggering false positives? I work in infection control on microbiology, so I think I have a good understanding.

Please advise.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hello,

Welcome to icliniq.com.

I can understand your concern. This can be a false positive. There is no need to worry if you are asymptomatic. I hope this helps.

Thank you.

Patient's Query

Hi doctor,

Thank you for the excellent and detailed response.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hello,

Welcome back to icliniq.com.

Can you send me a picture of that positive report? Exactly how old is that report? Because an asymptomatic carrier can transmit the disease.

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

What report should I attach?

We appreciate your comments and use them to make patient care better.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I am asking you to send me a picture of your positive lateral flow test. Do you have them?

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

I have attached the document(attachment removed to protect the patient’s identity). Please advise.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I can understand your concern. I have gone through the images you have attached (attachment removed to protect the patient's identity). The first one is not clear cut positive. It is indeterminate, you can say.

The second one is 100 % negative. So I do not think you should consider the first one as positive. Are these Abbott test kits?

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

I have done these 5 this morning, I think it is a false positive, the tests are Getein Biotech Inc.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I can understand your concern.

All results are negative, so there’s no need to worry.

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

My daughter has quite bad asthma, and my dad is 80 years old with asthma so just trying to ensure they are as protected as possible. That is why I take regular tests.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I can understand your concern.

Honestly, testing is usually recommended only if you’re experiencing symptoms such as weakness, fever, cold, or sore throat.

In my clinical experience, the 6-minute walk test can also help assess possible COVID infection. I hope this helps.

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

My blood oxygen level is currently 96%.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I can understand your concern.

Could you please let me know what your oxygen saturation level is while walking?

I hope this helps.

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

My resting heart rate is 60 bpm. My oxygen saturation is 96% at rest and 97–98% after walking. Could you please advise?

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I can understand your concern.

Have you measured the total distance covered during the 6-minute walk test? Also, do you have a history of smoking?

Thank you.

Patient's Query

Hi doctor,

Thank you for your guidance.

I quit smoking 15 years ago and am currently 46 years old. I have a home gym with a treadmill and an exercise bike. I gained some weight during the pandemic, but I’ve recently resumed training regularly.

Thank you.

Answered by Dr. Kaushal Bhavsar

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Hi,

Welcome back to icliniq.com.

I can understand your concern.

Yes, I recommend focusing on maintaining a healthy diet and regular exercise. Try not to worry excessively about COVID.

Thank you.

Medically reviewed by Dr. Meera Premanand
Published At February 1, 2022
Reviewed At February 19, 2026

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

Education:

BDS

Professional Bio:

Dr. Meera Premanand is a dedicated Dentist known for providing comprehensive dental care with a focus on patient comfort and oral health. She combines modern dental techniques with personalized treatment plans to ensure healthy smiles and long-term dental well-being for her patients.

This doctor is not available for online consultations on the platform anymore.

Same symptoms don't mean you have the same problem. Consult a doctor now!

Education:

MBBS

Professional Bio:

Dr. Kaushal Bhavsar is an experienced Internal Medicine Specialist and Pulmonologist with expertise in managing respiratory conditions such as asthma, COPD, tuberculosis, and lung infections, along with chronic illnesses like diabetes, hypertension, and metabolic disorders. He is skilled in critical care, pulmonary function testing, and evidence-based medical management. Dr. Bhavsar is committed to delivering holistic, patient-centered care for long-term health and respiratory wellness.    

This doctor is not available for online consultations on the platform anymore.

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