Home Monitor vs. Lab

[RI Mom]

I use the ProTime meter to check my 6 year old son's INR. However I do have concerns about reliability, as does my son's Dr. Last week I checked him on Tuesday and his INR was 1.9 (too low), the next day I went to the lab and it was 2.8 (in range). We did not change the dosage (he gets 4 mg. daily). Going to the lab poses BIG problems for me....my child loses his mind completely just with the thought of having to go to the lab. Usually he begins his crying and begging before we even pull into the parking lot. So the home monitor is way less stressful but I still don't know if I can trust it. In the literature that came with the machine, it states "a correlation value near 1.0 means the comparison is good". If I understand this, it means that anything 1.0 above or below 2.5-3.5 should be OK.....is that right??? My child is very small, just 42 pounds and I'm concerned about any INR that is out of range. Typically our Dr. would adjust meds. with an INR of 1.5 but then I am questioning the accuracy....YIKES!

Theresa
Mom to Idrees with CHD (partial AV canal and Pulmonary Stenosis-replaced mitral and pulmonary-failed homograft, now stented)
2 OHS, another this summer
INOVA Fairfax Hospital
Drs. Irving Shen and Lucas Collazo
INR Home Tester

 

[Ross]

If your using the ITC Protime unit, the 1.00 they are refering to is the ISI index of the reagent used in the cuvettes. Your son should have a prescribed INR range which I'm assuming is 2.5 to 3.5. The idea is to keep him in between those two numbers. Many of us are happy with anything between 2.0 and 4.0. You never want him to be below 2.0 knowingly.

Being that you didn't test at the same time as the lab draw, I can't really say what the problem is. It may or may not be the machine or it may or may not be the lab draw. Best advice is to test yourself on the machine and if you come up with .9 to 1.2 for yourself, it's fairly safe to assume the meter is accurate.

Thinking over your correlation statement:

The home tests compared to tests run at the clinic using
ProTime with venous samples (421 samples) had a correlation of 0.92. The home test results compared to
a reference laboratory results (368 samples) had a correlation of 0.87. These correlation values mean that
home testing is comparable to lab testing.

 

[catwoman]

I use the ProTime meter to check my 6 year old son's INR. However I do have concerns about reliability, as does my son's Dr. Last week I checked him on Tuesday and his INR was 1.9 (too low), the next day I went to the lab and it was 2.8 (in range).

RI Mom:

I can understand the problem with taking a young one who's been through the wringer to yet another medical appointment. My cousin has that problem with her 22YO son who was born with multiple physical and developmental handicaps, including MVR.

Was this a lab draw, or a test with another POC monitor (CoaguChek or INRatio)?
I'm assuming that your son's range is 2.5-3.5, since he has a mitral valve replacement.

I only ran one or two tests with my ProTime 3 beside my doctor's CoaguChek, and they differed by maybe 0.4; the PCP's CoaguChek was higher.
Considering your son's tests were run on 2 different days ....

Just for grins, I did 2 INRs in March, with my INRatio and on the PCP's CoaguChek, and the CoaguChek was 0.2 higher. I could probably get that difference running 2 consecutive tests on my INRatio, since the warfarin content of your blood isn't 100%, perfectly, evenly distributed.

 

[Blanche]

When we first got the monitor, our doctor required us to do comparison testing. Albert tested 3 times in one day, morning, noon, and night, and got a different result each time. He tested on the same monitor.

My advice to you is DON'T give up. I would suggest that you get articles that show the benefits of home testing, and accuracy the of home monitors take them to your doctor. You can do a Google search and find many research based articles. Also, search this Forum and "Must have Resources."

If you think I might help, please contact me.

https://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?from2=viewdecisionmemo.asp&id=72&

This article from Medicare provides many eveidnced based research materials on the benefits and safety of point-of-care monitoring (home monitoring). One does NOT have to be on Medicare to take advantage of the research they have provided in this article. But, the fact that Medicare endorses home testing does influence many.

 

[RI Mom]

Thanks everyone,

I called QAS and spoke to one of the nurses. They gave me some good tips on getting a full drop of blood in there so that I don't leave blood in the cup waiting while I get more. This may have been one of my problems. I don't feel that I was properly trained in the beginning. QAS merely did a telephone training with me. In fact, when I called the Nurse a few weeks ago, he put a request in with the training dept. to call me to schedule additional training.....guess what? No call!! I will have to track them down again. Given the fact that I am testing a young child, you would think that they would do a little more to ensure that it is being done properly but I guess business is business, right?

 

[ChouDoufu]

you really can't compare tests taken on different days. it may only be
24 hours, but there are so many variables that affect the readings.

and about those variables, youse experienceded guyse, would things that
affect inr on regular adults have an even greater affect on small children?

 

[Ross]

you really can't compare tests taken on different days. it may only be
24 hours, but there are so many variables that affect the readings.

and about those variables, youse experienceded guyse, would things that
affect inr on regular adults have an even greater affect on small children?

Adults or children, it all depends on that persons metabolism. Not really more or less, just depending.