Watching your glucose to detect Covid

I’ve been careful avoiding the Covid-19 virus. I was vaccinated twice last spring and I wear a mask in any public indoor setting.

My daughter married last weekend and I felt a need to let my guard down for this special occasion. Her wedding and reception took place in a backyard setting and that helped ease my concerns regarding the virus. But I was fully cognizant that the delta variant can be carried by vaccinated individuals. This is an increased risk from the variants that it replaced.

My plan, following the wedding day, was to closely monitor my glucose with my CGM. I also figured that I could monitor my blood oxygen levels with my fingertip pluse-ox meter and watch for any substantial degradation of my blood oxygenation. And if my glucose levels rose to levels above 180 mg/dL and resisted correction, I would then go get a PCR test.

I normally eat two meals per day, one around 11 am and another around 4 pm. Yesterday, my glucose trace on my CGM was well behaved between midnight and noon. I started a new infusion site at 9 am.

The glucose effects of my first meal started kicking in just after noon and rose to the 150-180 mg/dL range, higher than usual for me. I corrected twice during that bump with a 4-unit pump bolus and a 4-unit Afrezza bolus. The glucose trace finally responded to my corrections and I thought everything was back to normal.

Here’s yesterday’s trace.

I decided to skip my second meal and I was lucky that I did. My glucose trace started to steadily march up from 135 mg/dL at 6 pm to 228 mg/dL at midnight. I had gone to bed at 9 pm. At 1:30 am I woke up and my CGM surprisingly showed my glucose at 220+ mg/dL. A follow up fingerstick read 253 mg/dL.

I thought to myself, “this looks like a hyperglycemia event likely started by a Covid infection.” As much as I would have loved to roll over and fix things in the morning, I could not turn my back on this level of hyperglycemia.

I figured that my hyperglycemia could be caused by more garden variety triggers like a failed infusion site. Since I had just installed the current site at 9 am the previous day, it was possible that that site just did not gain full traction. I swapped it out. I injected 4 units of Apidra as an IM shot into my shoulder muscle. I also inhaled 4 units of Afrezza.

Here’s today’s glucose line.

Luckily, I was able to return to sleep after this rude 30-minute interruption and I slept until 6 am. As I was falling asleep I thought that if my sugar did not respond to the corrections I made, then I would get a PCR test in the morning to confirm a Covid infection.

When I woke up, my CGM read 100 mg/dL. So that undermines my Covid infection hypothesis. My pulse-ox meter consistently showed oxygenation in the 96-98% range.

The mystery to me is the fact that vaccinated people can catch and transmit the virus without feeling any symptoms. If I didn’t feel any symptoms, does that mean that my blood glucose levels would not be impacted either?

Looking at today’s glucose trace, I give myself credit for getting up in the middle of the night and swapping out the infusion site, taking the two corrections from an external source and drinking a full cup of water to thin out the glucose sludge in my blood vessels.

My corrections were not perfect as I did have to add a few glucose tabs around 7 and 11 am, but I count as a success the fact that the glucose level did not bounce to the high side after my corrections.

While I was up treating my high BG last night, I found myself sneezing more than normal. I do have seasonal allergies and I was sleeping with my windows open. So I just wrote the sneezing off as my usual seasonal allergies. But then I was reading this morning that sneezing is one of the top three symptoms that people infected with the Delta variant report. Should I go get a PCR test?


I’d go, if only to put my mind at ease. While you’re unlikely to suffer significantly, having received the vaccine, the risk of passing it on is real.
Oh, and don’t take any horse de-wormer if you do test positive!!


The main thing is if you think you might infect someone if you did not know.

I think the question to ask yourself is if you would do anything differently if you had a positive result. There isn’t really a treatment. If positive, you would isolate and ride it out. And if it got really bad, you’d go to the hospital.

So are you going to be around anyone?

You could wait a few days. While there are a variety of symptoms, fever is pretty much the one common thing everyone has. The fever may not be consistent, so you should check your temp several times each day. But after a few days, if you never have a fever, chances are you are fine.

There isn’t much downside to getting a test. So sure, you can just get one. But if you are positive, the only difference is that you will isolate. So are you isolating now anyway?

Being vaccinated, if you do have C19, you will most likely be fine. You’d just have to wait out the symptoms for a while.

To me the answer would come down to not wanting to infect others. So it would depend on how much possible interaction I had planned for the next week.


Terry, I gather it is quite strange for your glucose levels to rise so high for no apparent reason. Is the new infusion site working better for you?

If I had that high of a glucose level and I couldn’t figure out why, I would be worried about covid in this situation. It would drive me crazy not knowing why my levels rose so high. If changing the site has made your levels return to normal, then it seems to me that you have found your answer. I would not be concerned about 3 sneezes.

If you find your mind dwelling on maybe having covid, then I would get tested for peace of mind. I also would test if I was going to be around people while not wearing a mask.

I hope that you have some answers by now.


I don’t think knowing I was positive would affect my behavior much. I live alone and always wear a mask in public indoor spaces. I am, in essence, already isolating.

If I knew I was positive, I would likely try to set up an appointment for the monoclonal antibody infusion treatment. But that would be out of an abundance of caution.

I wear a tracker 24/7 that senses body temperature and my temps have been normal.

I certainly don’t want to infect anyone else and I don’t have any social activities planned for the next week or so.


Yes, the new site seems to be working normally for me. My after meal glucose following my first meal today topped out at 113 and is now below 90.

I do think that the site that I inserted yesterday morning just did not fully absorb. I think I’ll just take a wait and see position at this time.


This is similar to my plans/concerns for outdoor wedding in a few weeks. I plan to wear mask, but remove when with family I know is vaccinated.

However, a few weeks ago, I had outdoor lunch with several folks, all had been vaccinated. But 2 days later, the person next to me tested positive. I did get PCR, which was negative. A positive would have impacted my decision on travel and attending wedding. (After additional testing due to false positive rates). Then I was notified the other person’s retest showed negative.

So I may change my approach once there and adapt on situation/spacing/mask wearers.

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Good luck with your upcoming wedding event, @MM1. It’s a tough decision to balance your need to protect yourself from exposure to the virus with your need to be an active member of your social circle.

The fact that it is outdoors and that you are already vaccinated support showing up. Do your best to protect yourself and may good luck be on your side.

An update on my post:

I’ve now enjoyed over 18 hours time in range 65-130 mg/dL since noon yesterday. That supports the notion that my blood glucose aberration was most likely due to a new infusion site that never fully took root. The replacement infusion set that I placed during the night before last is performing well. I don’t believe that a Covid infection would have let my blood sugar off the hook so quickly and cleanly.

I decided to forgo getting the PCR test because I didn’t encounter anyone who was recently tested positive for covid and I don’t have any symptoms. Out of an abundance of caution, I will isolate (not much different behavior for my situation) for a week or so.

Thank-you to everyone for your thoughtful replies. When you live alone, it’s nice to receive that support, especially from people who understand the blood sugar game we play.


Yeah, if you have any concern, go get the test.
Being in a larger group activity is reason enough to go get the test.
That’s what they recommend.

When people get sick, they can get really sick, really fast - as u know.

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Thanks for your concern, @mohe0001. I surveyed my opportunity to get a PCR test and was put off by appointment availability 3-4 days out. It seems that there are several outlets that are primarily catering to the needs of airline and cruise-ship passengers. I am finding persuasive my overnight BG line as it argues against a covid infection. I don’t think that a covid infection is compatible with this overnight result.

I could be wrong, but I feel well, no fever, no cough, 97% oxygenation, and normal blood glucose. I will continue to monitor and change direction if appropriate.

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You can get Covid tests at home. You can order a few and keep them. Then you spit in it, and throw it in the mail.
You should get the results in 2 days.
I prefer it to going to a giant testing site


From what I’ve heard, the tell-tale sign is the loss of taste. But not everyone infected looses taste. I’ve also heard good things about monochonial antibodies. You have 10 days to get them infused after a positive PCR test. Here in St. Louis, MO there are 5 hospitals in the entire state that are doing it. Two are reasonably close. I also heard there is a third variant that has been discovered in the lab but not wild yet and might be resistant to vaccines.

My son had COVID19 and his tell-tale sign was when he lost taste. We fortunately didn’t get it. All 3 of us decided to get the vaccine (Moderna). At the time they were saying that even if you had it, the vaccine would help with other strains that you might not be immune to.

Stay safe out there everyone!

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Rapid antigen tests aren’t as reliable as PCR in that they can give a false negative, but they can still be helpful if you’re concerned but don’t have symptoms. My understanding is that false positives rarely occur.

The Abbott BinaxNow test in the link above is well- rated and provides results in 15 minutes (no need to ship it elsewhere).

I just bought a few from Walmart.

My state has walk-up sites (every day) that do not require appointments. They’re not as ideal as the drive through testing sites with CVS. Still, it might be worth checking to see if your state has that option for future reference. I’m not sure if the walk up sites are PCR or rapid antigen testing. Perhaps both? I plan to figure that out.

This is a good compromise. Drive-thru testing does nothing for me because I don’t own a car and the local drive-thru site is a distance away.

I like the idea that the cheap tests have a lower false rate for positives. I’ll check your link. Thanks!

Edited to add: I checked all three at-home covid-19 antigen tests at that wirecutter link and they are all out of stock!


This link for Walmart shows it as in stock, but it’ll take a week to arrive. I tried to link to it, but not sure it’ll work.

This is the same link in the wirecutter article. I think CVS is sold out though.

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Yeah, I just checked Amazon. I worry about the timeliness of the test going out another week. At this point, I think I’ll stand pat, unless some symptoms show-up. Thanks!

Interesting stuff. There’s a shortage of tests, according to Abbott Labs. Its good to get a report on how this is functioning in practice. Despite the shortage, if anybody needs one, check Walgreens. Abbott makes an over the counter test & sells it there. Minneapolis is setting up new facilitates to JUST perform testing. Your city might do something similar.

Free drive thru testing:

It’s now been 10 days since my possible exposure to covid-19. I do not have any symptoms of this virus and my current blood sugar levels are typical for me. I just wanted to give some follow-up and will no longer provide any additional updates unless other questions are raised.

This entire concern that I had was simply due to a coincident insertion of an infusion site that failed to take hold. Since it synched up with a significant relaxation of my avoidance of social groups, especially without masks, I had to take extra caution when considering unusual blood sugar excursions. I’m glad this was all just a false alarm!


Thanks for the drive-thru link, @mohe0001. Since I don’t feel any covid symptoms and I would need to rent a car to drive-through, I’ll remain untested at this time.

How is Portland doing, Terry4? I’ve had some recruiters reaching out from there. Links are just there incase anybody else has needs. I know your all set.