Engineering student designing a new anticoagulant monitoring device

[Chuck C]

I used to get 90 day supply, without insurance, for about $10. Now, with insurance, it's more like $25 -- still not a lot compared to dollars per pill for the newer stuff.

You might shop around. I get mine at Costco. Just double checked what I last paid. As of one month ago, my cost was $9.02 for a 90 day supply. This is their retail price, without any insurance discount.

Also, you can ask them to check the GoodRx price. It takes them just a few seconds to look it up and they will honor their price if it is less than the price you would otherwise pay.

 

[Protimenow]

Not a bad idea. I was trusting that with my AARP prescription plan (which implies that it gives me the best price), the price would approach Costco.

I may just start getting my stuff at Costco -- once my broken ribs heal and I can handle driving and walking through the store.

 

[pellicle]

once my broken ribs heal and I can handle driving and walking through the store.

from what I've seen you'll need some other strengths to handle that bit

 

[Protimenow]

from what I've seen you'll need some other strengths to handle that bit

Actually, they have motorized carts at Costco. I CAN actually drive (one of those carts) through the store.

I don't plan on doing this -- doing so will make me feel old or disabled

 

[pellicle]

Actually, they have motorized carts at Costco. I CAN actually drive (one of those carts) through the store.

was meaning the strength required for "dealing with the idiots"

 

[Protimenow]

Sometimes I have to try to avoid the idiots. Costco isn't quite as helpful as I'd like - they have to actually GET the prescription before they can tell me how much it costs. They didn't do this in the past.

I have enough warfarin for at least 90 days. By then, my ribs should be completely healed and I may actually 'enjoy?' going through Costco to get to the pharmacy.

 

[Chuck C]

Actually, they have motorized carts at Costco. I CAN actually drive (one of those carts) through the store.

I don't plan on doing this -- doing so will make me feel old or disabled

I've always suspected that at least 50% of the people driving those motorized carts are doing it for the thrill and not because of a need. Of course, I have no actual evidence to prove this

 

[Chuck C]

I have enough warfarin for at least 90 days. By then, my ribs should be completely healed and I may actually 'enjoy?' going through Costco to get to the pharmacy.

Just be careful about the free food samples they give out at Costco. I've seen seniors throw elbows to gain position for half of a free mini weiner dog. That's the kind of hazard that could set your healing ribs back 3 months.

 

[Protimenow]

I avoid those damned things and try my best to go around them. I've heard of some people actually going there for lunch -- the samples. I'm waiting for someone to open a sample packet of dishwasher soap and try to eat it.

I can't imagine putting some of that sample stuff into MY body. (Trying to keep away from pork and shellfish, and keeping 'sort of' kosher helps me to avoid that stuff -- plus not liking a lot of the fillers they put into that stuff also makes avoidance easy).

When Covid was at its height, these poor minimum wage demonstrators weren't there. I was grateful for that. They also had early hours for Seniors - getting in 30 minutes before the others helped me get some of the stuff that would otherwise have gone more quickly. No - don't bring back Covid on my account.

I find that around 3 PM or so usually is a good time to go to Costco.

As far as carts are concerned - I don't think I'd find a lot of joy running around in a motorized cart at the store, but who knows what others feel?

 

[pellicle]

I find that around 3 PM or so usually is a good time to go to Costco.

if you google a store (on a computer) and scroll down you'll find this handy graph

I often use that to choose when I go ;-)

HTH

 

[Sammy Elashy]

View attachment 889614

Thank you for the graph pellicle. Our goal is to design a device that is more efficient than the ones on the market by using refractive index to measure prothrombin time and INR. Theoretically with this prinicple, you don't need test strips that expire like coaguchek or any moving parts like the moving wheel in coag-sense.

 

[pellicle]

Theoretically with this prinicple

So @nobog was on the money then

 

[Sammy Elashy]

No at all, the device would work similar to how coag-sense, where you put the blood sample in a reservoir strip. It's just the ours won't require a moving part like the wheel they have if that makes sense.

 

[Sammy Elashy]

We want to minimize any points of failure and reduce costs by not requiring chemical test strips that can expire. We're still working on the design and seeing if this can actually work.

 

[Protimenow]

Thank you for the graph pellicle. Our goal is to design a device that is more efficient than the ones on the market by using refractive index to measure prothrombin time and INR. Theoretically with this prinicple, you don't need test strips that expire like coaguchek or any moving parts like the moving wheel in coag-sense.

This test wouldn't need reagent values, then. Right? What divisor would it use to calculate INR? Or would it even need one?

It would just use a refractive test to determine actual clotting time -- and somehow calculate an INR?

Would this work without strips? What volume of blood do you expect this to use?

I suspect that there MUST be some kind of consumable, if only to avoid cross contamination of specimens between tests.

I'd like to learn more about your approach.


Reducing costs is a great target - the way things are today, there are significant costs in testing and obtaining approval (perhaps matching results of your meter against results from lab tests and other meters (Coagusense apparently got approval, in part, by comparing results to the CoaguChek XS, IIRC), may speed up the approval process.

But there are a lot of front-end costs involved that will have to be covered (perhaps you can get a sizable grant to do this) so initial manufacturing costs can be kept low.

If you ever create a prototype, you can send me private mail about a user trial.

 

[Sammy Elashy]

I'd like to learn more about your approach.

So the reservoir that holds the blood would be the consumable because it would be contaminated, which can be considered the test strips if you'd like. Regarding how to calculate INR and what divisor to use, we're still in the early design process, so we're not there yet. It would calculate INR based on the clotting time determined by the refractive test.

 

[Protimenow]

Current tests use a reagent to stimulate clotting.
INR is calculated by dividing PT by reagent value.
With just a reservoir to collect the blood and your refractive mechanism, would you be able to determine an INR without a divisor? Wouldn't there be a slight variation between blood volume (even if it's in microliters) affect the clotting time (and, thus, your test results)?

I would certainly welcome a $50 meter that uses reservoirs that cost less than $1.00 and that could, if possible, go to Third World countries, clinics globally, and people who otherwise couldn't get to facilities for testing (and who would be able to self test and maybe self manage).

Democratizing the testing of INR would be a great thing -- and if your idea actually comes to fruition, it would be a great thing.

Of course, the way things go, a month after you gain approval, a medication will come out that will replace warfarin for coagulation control, maybe from a company that isn't especially greedy, and would make the use of such meters unnecessary.

 

[Sammy Elashy]

With just a reservoir to collect the blood and your refractive mechanism, would you be able to determine an INR without a divisor? Wouldn't there be a slight variation between blood volume (even if it's in microliters) affect the clotting time (and, thus, your test results)?

That's a very good point actually. A divisor or control PT is needed to determine INR becuase the patient PT time by itself is not enough to calculate the INR value. Refractive index is an intrinsic property, so the volume shouldn't be an issue.

 

[Protimenow]

I believe the strip makers use a reagent to get the blood to clot in a faster, more predictable way. LABS use a reagent. It's the material that provides a divisor. I'm not sure that other factors (temperature, for example) may be as important in the refractive measurement as they are in the 'tilt table' or impedance measurements in the other meters - both heat the 'strips' before a test can be run.

I'm also pretty sure that the refraction of 30 ml of blood in the process of clotting will change much more slowly than that of 10 microliters of blood (probably the amount on your consumable). A difference between 10 microliters and 11 or 9 MIGHT make a difference (possibly insignificant because this is a variance of +\- 10%) in your results.

You've got some challenges. I hope you can design a reliable, inexpensive meter that can be seen as an alternative to the two approved for use in the United States, and the others being used in other areas.

 

[pellicle]

No at all, the device would work similar to how coag-sense,

Which requires blood to leave the body, be exposed to a trigger and clotting time measured. Do you understand how that is measured?

You seem to be talking about a magic method of determining this under the skin.