A Protime/Coagucheck question

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Bonnie! One lucky lady. Happy your levels are coming up so quickly! It takes me well over two weeks at times!

Was thinking about posting a post holiday INR thread. Not so sure if I can count myself...exercising like a fool:D My levels are sure to be low. Hopefully not!

Have a great trip and Happy Thanksgiving.

PS. Anyone have a good recipie for
'Southern Egg Plant Au Grautin'? Had a fantastic one at a B & B down in Arkansas. Should have asked the cook.:mad:
 
Well, to update everyone....Tyce had his protime done today by our unit, ITC"s unit and the cardio's coagucheks....2.5 on ours, 2.2 on ITC's and 3.9 on the cardios 2 units......I placed a call to ITC, but they're probably going home because of the SNOW ALERT, as Jersey got mucho snow before it started on LI. We have about 1-2 inches already on the east end, and it's still coming. This isn't even the storm we're going to be really hit with tomorrow!!!

Anyway, back to this problem...does anyone have any idea what we should do concerning the difference.....ANY suggestions are welcome!!! Thanks

Evelyn
 
Evelyn:
So sorry. I hoped that this would be solved by now. Regarding the differences between results, you might want to consider doing nothing. Although Tyce's INR does not need to be above 3.0 for AVR, it is very unlikely that 3.9 will cause any harm. Albert's range, because of his stroke and MVR, is 3.0 to 4.0. I remember that Al Lodwick has said that he does not worry until INR reaches 5.0. Also, there seems to be consensus here that higher is better than lower. I wish you strength and will keep you in my prayers.
Blanche
 
It almost makes me wonder if there is a difference due to the different reagents, I think they're called thromboplastin agents or whatever, that the two systems use and maybe they each measure the combination of clotting factors differently - but supposedly the INR is supposed to standardize all that. I also suppose you need a tie-breaker - impartial third test (maybe a venous draw) at a different facility.
It reminds me of the saying: a man with one watch knows what time it is, a man with two watches is never quite sure.
Is your doctor going to leave the current dose of coumadin though their machine says it is 3.9? If I recall the last tests with the Coagucheck were around 2.5 - should it have gone up to 3.9 on the same dose?:confused:
 
This is a tough call.

If I had only one test result here is what I would do.

2.2 = increase by 15%

2.5 = do nothing

3.9 = do nothing

But you have 3 tests so - since 2 of the 3 are do nothing, I would probably do nothing but keep the same dose and test in another week.
 
Hi Al and Jim

So glad you're back safely, Mr. L.....

Was on the phone with ITC this am---they can't figure it out, either. Tyce's last test last Thursday was 2.0 and 2.5 on our two Protime's (ours 2.0, ITC'S 2.5) and 3.9 on the cardio's Coagucheks. I think they're beginning to think it's the cuvettes, but we have 2 and now 3 batches to draw from. Lakeesha (the ITC service tech) is having our cuvette lot numbers used in their clinic this week to see what they draw in clinic. Our cardio wanted Tyce to reduce another day from 5 to 2.5, but we're not doing it....2.0 is too low for me. So for right now, he's on 5mg 6 days a week and 2.5 one day. We're testing on the two protimes's on friday, so will let you all know......it's getting very frustrating!!

Did you eat lots of chocolate, Al???

Evelyn
 
I took my protime monitor to the hospital lab yesterday. I was nervous about using it in front of someone but it went fine. The lab manager was interested in seeing how it compared to the lab draw. It is the first medical person I have found in my area that even knows home testing is possible. The monitor read 3.5. The venous draw was done immediately and the results were ready in 15 minutes. The lab draw was 3.3. I have more confidence in the home machine now. I only knew about Coagucheck and the protime machines. QAS notified me when Medicare began paying and I never heard from coagucheck although I had talked to their salesman many times. loann
 
5 channel or 3 channel cuvettes?

5 channel or 3 channel cuvettes?

I only use the 5 channel cuvettes. I found inconsistancies with the 3 channel and now stick only to the 5 channel.
I recently tested against the lab and only had a .1 difference.
Sorry your machine is out of wack. That would be a royal drag after spending the big bucks to get one.
Hope they can fix the problem to your satisfaction.
Gail
 
Can you use the 5 chanel cuvettes in a Protime machine designed for the 3 channel cuvettes?
 
Cuvettes

Cuvettes

If you have a ProTime 3 channel monitor, you can use either cuvette (3 channel or 5 channel). However, the older monitors, purchased before 2001, you can only use 5 channel cuvettes. If you want to see which device you have, simply call ITC and give them the serial number. Thanks!
 
Hello All

Has been a bit since I've posted about our Protime monitor.....actually thought all was back in stride, but unforturnately, it's not.

Yesterday, Tyce had a cardio appt....PT test and ekg, ov, just to make sure all was well. Soooo.....we get up and check his Pt on our two protime machines.....2.3 and 2.6...."Good!!!" I think....will be in range when we go to the cardio's office.

WRONGO!!! Their coaguchek was 5.0 (again) Off to the hospital for a comparison lab draw.....would you believe 4.8!!!! DUH!!!

I'm willing to listen to ANY opinion of why this has happened, yet again. Seems no one at ITC can figure it our, our cardio says he has no idea why, and quite frankly I'm ready to dump the Protime machine and bite the bullet and buy a coaguchek so we can be in line. The scary part is that I don't know who to believe....hospital lab draw, cardio or ours???????

On the good side, cardio said Tyce's ekg is great, PVC's which were always present before surgery have totally disappeared and he sounded "rock solid" on chest exam. He'll see him in 2 weeks for another protime test and then 6 months for his echo....now down to once yearly.....YAHOO!!!

Thanks for letting me vent.....again!

Ev
 
When push come to shove, doctors will always go with the hospital lab as the standard to which others should be compared.
 
With the Doctor' Coaguchek S and the hospital lab results being nearly Identical - I wonder if it's possible that the Doctor's coaguchek's have been calibrated to reflect the hospital lab inr's in a quality control procedure.

At the risk of becoming a pin cushion wonder what would happen if you got yet another test from a lab not connected with your doctor or the hospital.

What a mess that both sets of results would be out of range for a 2.5 to 3.5 therapueutic range - one too high, one too low - what do you do increase or decrease?

This seemed liked it'd be an interesting article where they say even with the INR - different thronboplastin reagents can give significantly different INR's for the same sample of blood, even when they used the same testing machine.

From:
http://www.csanz.edu.au/abstracts/49abstracts/131.htm
>>>>
CLINICAL SIGNIFICANCE OF INTERNATIONAL NORMALISED RATIO (INR) VARIABILITY WITH THE USE OF DIFFERENT THROMBOPLASTINS

J.E. Bray*, E. Malan, T.E. Gan, R.E. Peverill.

Centre for Heart and Chest Research, Department of Medicine, Monash University and Monash Medical Centre and Haematology Department, Monash Medical Centre, Clayton, Victoria.

Commercially available thromboplastin reagents used for the determination of the prothrombin time vary in their response to coagulation factor depletion and each is assigned a value of the International Sensitivity Index (ISI) which is used for calculation of the INR. The INR/ISI system was designed to correct for differences between thromboplastins and coagulometers but it is now clear that complete normalisation cannot be achieved. The aim of this study was to investigate the variability of INR levels with some thromboplastins in common use and to determine the clinical significance of such variability.

METHODS: We compared INR values using three thromboplastins, Innovin (I), Thromborel S (T), and RecombiPlasTin (R), in 65 patients with mechanical prosthetic valves. To control for differences due to coagulometers, all assays were performed on an `Il Futura' instrument. The ISI of each thromboplastin was calculated manually using calibration plasmas. INRs were divided into three ranges <2.5, 2.5-3.5, and >3.5, with a difference between INRs defined as `clinically significant' if the INRs fell into different ranges. RESULTS: Comparing I and T, there was a large difference in mean INR (3.5 vs 2.8, p<0.001), only a moderate correlation between the INRs (r=0.75) and 32 (49%) `clinically significant' discrepancies. Comparing T and R, there was a moderate difference in mean INR (2.8 vs 3.2, p=0.001), a moderate correlation between INRs (r=0.81) and 20 (31%) discrepancies. While there was a strong correlation between INRs using I and R (r=0.96), there were still discrepancies in 12 (19%) and a moderate difference in mean levels (3.5 vs 3.2, p=0.03). In individual patients INR levels with different thromboplastins differed by as much as 2.5.

CONCLUSION: In conclusion, these results confirm that the INR does not adequately standardize for different thromboplastins even with the use of a single instrument and manually calculated ISIs. Clinically significant differences were evident in up to 50% of cases and this could be even higher in the community with the use of different coagulometers.
>>>>

here were a couple more articles that mentioned variability-

From:
http://www.4s-dawn.com/dawnac/dawnug2001/benchmark.html
>>>>>
All oral anticoagulant management clinics rely on some form of Prothrombin Time measurement, usually expressed as an International Normalised Ratio (INR). Different testing systems exhibit different characteristics in terms of sensitivity to various clotting factors. Local variations in the choice, calibration and standardisation of INR systems can impact on patient time in range. The cross-calibration of different INR methods at the same site can be a particular problem.
>>>>>

From:
http://www.blackwellpublishing.com/abstract.asp?ref=0007-1048&vid=122&iid=6&aid=11&s=&site=1
>>>>
British Journal of Haematology
Volume 122: Issue 6
European Concerted Action on Anticoagulation. Correction of displayed international normalized ratio on two point-of-care test whole-blood prothrombin time monitors (CoaguChek Mini and TAS PT-NC) by independent international sensitivity index calibration
Summary
The international normalized ratio (INR) on two widely used point-of-care test (POCT) prothrombin time (PT) monitors (CoaguChek Mini and TAS PT-NC) differed considerably and also differed from the â??trueâ?? INR obtained on the same samples using a manual PT and the same species thromboplastin international reference preparation. Agreement between the displayed INR and difference from â??trueâ?? INR has been reassessed following an independent international sensitivity index (ISI) calibration of the two systems. The displayed INRs taken at seven centres were compared with â??trueâ?? INRs from the same blood donations and INRs based on the resulting ISI. The overall difference between the displayed INRs on the two monitor systems was reduced from 21·0% to 3·5%. The overall difference in mean INR of system A from the â??trueâ?? INR was reduced from 19·0% to 9·5% and of system B from 6·8% to 0·3%, but individual centre's results still showed considerable mean INR variability. Differences between overall displayed INR with the two monitor systems have been reduced by an independent multicentre calibration, and agreement with â??trueâ?? INR on the same blood samples improved. However, marked variability in mean INR at individual centres remained after ISI correction, which demonstrates the need for external quality control of individual POCT whole-blood PT monitors.
>>>>
 
With the Doctor' Coaguchek S and the hospital lab results being nearly Identical - I wonder if it's possible that the Doctor's coaguchek's have been calibrated to reflect the hospital lab inr's in a quality control procedure.
Hey Ev, doesn't this sound like something I said?

I'm sorry but I do not think that lab veinous draws are accurate. Too many variables come into play between technician taking the sample and the tech running the tests. I read the proper technique for acquiring the sample and I can say without doubt that the lab I was going to, only did it properly maybe 45% of the time. There was only one guy in there doing it the proper way.
My INR was all over the place on the same dose. I got sick and tired of it after reading the technique and switched to a fingerstick clinic and ever since, my INR has been pretty well stable.
 
I do not think that there is any way for a user to set the calibration of a CoaguChek.

Different thromboplastins will give different PRO TIMES not different INRs. That is what the INR was devised to correct.

The above statement is true only when the pro time is close to the therapeutic range. If the ISI of the thromboplastin is not 1, then the INR becomes less true the further from the desired range that you get. (The current ISI of CoaguChek is 2.0 but that is about to change - as Marty told us.)

The values that Evelyn gave are not far enough apart that the ISI could be much of a factor.

As far as what will happen to Tyce there is very little difference between an INR of 2.3 and an INR of 5.0. You could probably go years at either level without anything significant happening.

As every one of you has experienced, blood clotting is not an exact science. Hundreds of times I have run QA checks on my testers. We have the lab tech do a venous draw and from the syringe put a drop on tester A, a drop on tester B and squirt the rest in a tube to go to the hospital lab. It probably does not happen one time in 50 that you get the same result from all three tests. We have probably used more than 10 different CoaguCheks (we have 3 in constant use), two different lab testers and one Pro Time. The results are always random. No machine nor method always gives the highest or lowest results.

To further mess up those who like pin point accuracy, remember that the "therapeutic ranges" were set by a committee. We don't know what the committee's raw data showed. Maybe there was evidence that there was not much difference between 2.0 and 4.0 but there was a powerful personality of the committee who wanted 2.5 to 3.5 so that is what was finally voted on. You have all been on committees and know how the politics plays out.

After seeing more than 20,000 visits and having several different statistical analyses done on the results, I have boiled it down to, "avoid getting more than 0.2 units below your range and try to stay below an INR of 5.0" This has resulted in my patiens having a minor bleed (usually nose) about every 18 months, a serious bleed (requires 2 units of blood or into the head) about every 33 patient-years and a clot about every 100 patient-years.
 
Central Lab vs. Coaguchek

Central Lab vs. Coaguchek

There is one doctor who is not impressed with central labs and that is Dr. Jack Ansell in Boston. He saved me lots of time and trouble when he stated my little old Coaguchek was as good or better than any central lab. I have not been to a central lab now in almost four years.
 
Thanks all!

I think for now we'll just go with the cardio's coaguchek and have Tyce tested every two weeks. His dosage was 5 mg. every day. Our cardio wanted it to change to 5 mg. 5 days and 2.5 two days....think we'll do 2.5 only one of those days.

I do plan to contact Coaguchek and see what they're offering and then contact Tyce's insurance and mine to see if they will cover anything before I do anything.

Peace.

Ev
 
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