COVID-19 Diagnosis and Isolation: Key Questions Answered

Some issues related to COVID-19 diagnosis?

I'm sorry, but I don't know which specialty to ask.
On the afternoon of October 14th, I suddenly felt a strong urge to cough, and it was severe.
Even after getting home from work that night, I took a rapid test which came back negative.
The next day, I had a day off, and my voice was noticeably hoarse, plus I had a fever.
I went to see an ENT doctor (at a clinic), who didn't provide any treatment but prescribed medication and advised me to take rapid tests for the next two days, suggesting that the viral load might not be sufficient to test positive yet.
After taking cold medicine for three days, I felt somewhat better.
On October 18th, during my company's weekly routine rapid testing, I tested positive.
I immediately went to the emergency room downstairs (since I work at the hospital), where the doctor confirmed the diagnosis and reported it, prescribing oral antiviral medication.
That night, I began home isolation for seven days (until October 25th).
Two days after reporting my diagnosis, on October 20th (yesterday), my rapid test was already negative.
On the night of October 19th, there was still a faint second line on the test, but by October 20th, it was just one line (after taking the antiviral medication).
1.
Since my rapid test is negative, do I still need to continue isolating from my family members until the 25th? (I plan to follow the government's guidelines and stay isolated until the 25th, but what about my family members?) (I can stay in a separate room, but we share a bathroom, so I disinfect it thoroughly after using it.)
2.
Is it possible that I had the virus on October 14th when I first showed symptoms, but the viral load was too low to test positive? By the time I tested positive on October 18th, it had already been four days, and by October 20th, it had been six days.
Am I still contagious to my family members? (Since I reported my diagnosis, my family members have all tested negative.) My dad went to the pharmacy to buy something he needed and asked the pharmacist, who said that I might have had the virus when I first showed symptoms, and by the time I tested positive, the viral load had decreased, but it was still detectable (lower transmissibility).
3.
If it were just a simple flu or cold, is there a possibility that the COVID-19 rapid test could still yield a positive result? (The accuracy is not 100%.) Is it possible that I don't have COVID-19 but just a regular cold? (I've been wearing a mask for over a year and haven't caught a cold.) I really want to hug my pets at home.
😭😭😭 Seven days without being able to hug them is too painful.

Ms. Wu, 20~29 year old female. Ask Date: 2022/10/21

Dr. Hong Yuanbin reply Internal Medicine

Hello,
1.
It is advisable to maintain a proper distance for the time being, as there may still be a low viral load present.

2.
Yes, that's correct.
When the viral load is low, there is a possibility of false negatives.

3.
No, currently other diseases do not cause false positives in COVID-19 tests.

In summary, it is still recommended to wait for 7 days for safety.
Thank you for your question.

Reply Date: 2022/10/21

More Info

Understanding COVID-19 Diagnosis and Isolation: Key Questions Answered
It sounds like you've had quite a challenging experience with your recent COVID-19 diagnosis, and it's understandable to have many questions regarding isolation, transmission, and the nature of the virus itself. Let's address your concerns one by one.

1. Isolation After Testing Negative: According to current guidelines, if you have tested negative for COVID-19 after being diagnosed, you may not need to continue isolating from your household members, especially if you are no longer exhibiting symptoms. However, it is crucial to follow local health authority guidelines, as they may vary by region. Since you mentioned that you will be isolating until October 25, it is wise to adhere to that timeline to ensure you are fully cleared of the virus and to protect your family. If you have a separate room and are practicing good hygiene (like using alcohol spray in shared spaces), you are taking the right steps to minimize any potential risk.

2. Timing of Symptoms and Viral Load: It is indeed possible that you were infected with the virus on October 14, but the viral load was not high enough to be detected by the rapid test at that time. Rapid tests are known to have limitations, particularly in the early stages of infection when the viral load is low. By the time you tested positive on October 18, the virus had likely multiplied to a detectable level. As for the infectious period, studies suggest that individuals are most contagious in the days just before and after symptom onset. Since you have tested negative after a few days of treatment, the likelihood of you being contagious at this point is significantly reduced, especially if your family members are also testing negative.

3. False Positives and Other Infections: Rapid antigen tests for COVID-19 are designed to detect specific proteins from the virus. While they are generally reliable, they are not infallible. It is possible, though rare, for a rapid test to yield a false positive result, particularly if you have another respiratory infection. However, given your symptoms and the context of the pandemic, a positive result is more likely to indicate a COVID-19 infection rather than a common cold or flu. If you have concerns about the accuracy of your test results, you might consider a PCR test, which is more sensitive and can provide a more definitive diagnosis.

In summary, your current situation seems to be improving, and you are taking the right precautions. It is essential to continue monitoring your health and follow the guidelines set by health authorities. If you have lingering symptoms or concerns about your health, consulting with a healthcare provider is always a good idea. They can provide personalized advice based on your medical history and current condition.

Lastly, it's understandable to miss your pets during isolation. Once you have completed your isolation period and are symptom-free, you should be able to resume normal interactions with them. Take care of yourself, and I hope you feel better soon!

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