Which would YOU trust?

[Protimenow]

I'm aware that there probably aren't many on this forum who use the ProTime meter, or its successor, the ProTime 3.

I also realize that the CoaguChek S has been discontinued and won't receive support after next October.

In an earlier set of tests, my ProTime 3 and CoaguChek S produced the same result.

Today, the CoaguChek S showed a 4.3, which was slightly troubling to me. I figured I'd drop my dose for one day and then test in three - but I wanted to confirm with my other meter.

The ProTime 3 gave me a 3.6 - still slightly high, but much less troubling.

Here's my question: which would YOU believe?

In my case, because the ProTime 3 has internal quality controls on the cuvette, and it matched a test taken in a hospital last December; and because the CoaguChek S requires QC testing, I choose to trust the results of the ProTime 3.

I'm sure that many of you have probably used the CoaguChek S in the past, upgrading from that meter to an XS or an InRatio, but I'm interested in your past experiences with this meter. I got it new, and the only QC test it probably ever had was when it was manufactured (and when I compared its value to the value of the ProTime 3).

Any thoughts?

 

[ALCapshaw2]

Hard to say. You would probably need to do more comparisons with Lab Draws to feel more confident, but even Lab Draws can have some margin of error.

That said, my Coumadin Clinic uses the Coaguchek XS machines and their experience is that they read on the High Side, especially for elevated INR's. I am aware of a couple of XS readings in the 5.0 range that came back in the 4.0 range after a Lab Draw.

'AL Capshaw'

 

[Lynlw]

Did you do a repeat test on either machine?

 

[Protimenow]

Thanks, Al. I've reported in other posts that the XS can report high INRs to be higher than lab draws.


As for Lyn's question - No I didn't repeat on either machine - though I was thinking about doing it again on the CoaguChek S because the strips are ready after five minutes out of the refrigerator and the results are delivered more rapidly.

24 hours later (now), I may just repeat with the CoaguChek S and see with it reports.

Thanks for the suggestion.

 

[Jkm7]

Do you never compare your home testing to a lab's?

 

[Protimenow]

Yes. In December, I had a concussion. The day before, my ProTime meter said 2.9. The day of my accident, the hospital lab said 2.92.

Certainly close enough, I thought, for me to trust my ProTime.

 

[Jkm7]

That's about as close as you can get. But December was 10 months ago.

 

[Cris N]

I think it's important to remember that INR can fluctuate during the course of a day. I reported an experience when I was going to an ACT clinic and the nurse asked me if she could test me several times just to see what the machine (Coaguchek S) reported. We did three tests... I don't remember the numbers at this point but there was a much wider variance than one would expect. Something like 2.5, 2.9, and 3.2. This was over the course of about 10-15 minutes.

I've learned to trust my machine and not test too often lest I become obsessed.

 

[Protimenow]

Yes, I wasn't TOO concerned - but that 4.3 on the CoaguChek S got my attention. The lower value a few hours later on the ProTime 3 made me feel a bit better - I dropped the dosage just a blt (I usually take 7 mg/day, but took only 4 mg yesterday), hoping to fall back into a safer range.

I'm thinking, too, that it took me more than 15 seconds after incising my finger to get that little drop on the CoaguChek S strip. I would think that, since the blood may have already started clotting (or the platelets were diluted more than the machine was calibrated for), the result wasn't accurate. Plus, the CoaguChek S DOES report higher than normal at higher INRS -- so a 3.8 (as reported by the ProTime 3) may have shown up on the CoaguChek S as a 4.3.

Perhaps I was worrying about nothing.

jkm7 -- good point about the test being 9 months ago. The two quality control tests built into the ProTime 3 cuvettes keep me trusting this meter.

Thanks all for the great responses.

 

[lance]

Promtime now
What is so distressing about 4.3? My range is 3.5-4.0. 4.3 doesn't cause me to blink.
AND
My XS has on many occasions tested the same as the lab so I don't understand why you feel yours tests higher. I also can't understand why you use two monitors. Overkill if you ask me or are you looking for problems and hoping to find them.

 

[Protimenow]

Lance: My CoaguChek is an S, not an XS.
I've been using the ProTime meters for more than a year, and reading how everyone seems to prefer the CoaguChek and InRatio meters to the ProTime. For $40 delivered, I was able to get the CoaguChek S to find out why it was preferred. I got the CoaguChek PT strips for about $3 a test.

The CoaguChek S has a reputation for going higher than actual values when you're at 3.5 (or so) and above, and I was surprised by the 4.3 (even if it may have been more like a 4.0 on a lab test).

With my Aortic Valve, I'm expecting to keep somewhere around 2.5-3.5. The 4.3 seemed a bit anomalous and I didn't consider that CoaguChek S WOULD score high in that range.

And no, I'm certainly NOT hoping to find problems - that's the LAST thing I want - but, if I DO find a real problem, I'd be able to react more rapidly (half doses?) than someone who only tests once every month or two -- and now that I've got supplies for a test a week, I'm taking advantage of this fact before the strips expire (ProTime in March, CoaguChek in June)

One other thing about having more than one meter -- if one of them fails, I've got backup.

 

[Gail in Ca]

Some time ago, I was sent protime 3 cuvettes, not the 5 channel I had always used. I used one, and then repeated the test on the other hand with the 5 channel. The results were more than .2 off. I repeated this the next day, same results. So, I have stuck with the 5 channel since then. Now, I have my Coaguchek XS, and I've only used it twice while being trained to use it, and the results were only .1 different. I guess I could test with the new machine and then with my old protime 5 and see how the results might differ. But, one really must stick with one machine, I think. Now, if the results are way off from what you have been getting, then repeat in a day or 2, and see what you get. If they are still far off, I would go to the lab just to see what result is the closest to which machine, or in my case, I went to my cardio nurse, she tested me with her machine, then I tested myself with my machine. It was only .1 different.

 

[Protimenow]

The only ProTime cuvettes I've used were the 3 channel. These tested extremely close to the value the next day at a hospital's lab. When I got my last batch of strips, I was concerned that they were allowed to sit on a hot UPS truck all day before being delivered -- but comparing the HOT cuvettes to the ones I still had in the refrigerator, the results matched.

I've done testing with my CoaguChek S and the ProTime - the first time, the results were exact. The second time, there was the difference - possibly due to the S overstating higher results.

One bit of advice -- if you want to compare results of the CoaguChek XS and the ProTime meter, remember that the CoaguChek XS wants the first drop - within fifteen seconds of the incision. The ProTime wants later drops (they suggest wiping away that first drop -- I'll bet that wiping it on the XS strip would meet their requirement). If you time it right, you may be able to get the test on both meters with one incision -- the first drop will go to the XS, the rest will go into the Tenderlette and then into the ProTime. Testing a day apart won't provide a fair comparison - but testing on both machines, preferably with a single incision, should be the gold standard for comparisons.

Oh - and suggesting that you should only use one machine is a good suggestion. With the ProTime and ProTime 3, I've only used the 3 channel cuvettes -- and I'm assuming that even if the results may differ from those of the 5 channel (and I don't really see why they should), the 3 channel results are, at least, consistent. The CoaguChek S gives a faster result and seems to take less blood (if I'm able to get it onto that small hole), so I've been using that too. Plus, it has a quieter beep than the ProTime 3, and doesn't upset my dog like the ProTime 3 does. I realize that the results won't always match those of a ProTime test - but when either meter reports results that are out of range, I'm able to use the other to retest and see if I've got a possible problem.

 

[Protimenow]

One other thing about my use of two machines (and, if I can get an InRatio or XS, I may switch again): I've decided to base my usage on the number of strips I have left until they expire. My ProTime strips expire in March - I don't think I'll use them up before then. My CoaguChek S strips expire in June. So, I'll probably be using the ProTime until the strips expire, and then switch to the CoaguChek S.

Even if I test weekly (which is probably more than necessary), I still may not run out of 'strips' before they expire. So, just to compare the two machines, I may still follow a test on the S with one on the ProTime meter.