the 15 second rule

[pellicle]

Hi

my coaguchek makes it clear that the blood must be applied to the test strip within 15 seconds of lancing. To be honest unless I cut the tip of my finger with a knife I am never going to bleed that fast.

I have tried the deepest setting and only result in a higher sting and bleeding for longer.

What are others finding here? I don't even start till the 20 second mark.

 

[ski girl]

My coaguchek gives me 180 seconds!!!

 

[pellicle]

I believe that your coaguchek gives you 180 seconds to apply the blood from the end of the test cycle, the documents I have say 15 sec from lance to application. I was bitching about this today with the reps
from the manual and from the quick reference guide

 

[JimL]

I find it much easier to get blood for my test at home than after driving to the coumadin clinic through winter weather. At home, my fingers are warm and usually full of blood. I spend time--while the machine is getting ready to do something--pushing the blood to the tips of two or three fingers on my right hand; then when it's finally ready, I use the lancet, push out as big a drop as I can, and apply it. You could try running warm water over your fingers first.

 

[pellicle]

Thanks for your reply

I find it much easier to get blood for my test at home than after driving to the coumadin clinic through winter weather

I bet

But are you within 15 seconds? Have you ever timed it?

 

[ski girl]

Huh, I did a good job of reading that! My book says the same thing. I have no idea if I get the blood out within 15 seconds, I'll have to time it when I check next. I do the fingers under running water thing too, and make sure I'm well hydrated, and use the deepest lance setting. If the blood seems slow in coming out I whack the finger with the lance a second time.

However about 50% of my attempts are 'error' something or other in which case I just get frustrated and give up for the month. Don't tell my cardiologist.

 

[JimL]

I agree that I never time myself on that. I'm too busy getting the blood out, which is my job. If the machine is in a prissy mood, it might beep and give me some number, probably 5, that it's taken too long. I try hard to let it not ruin my whole day.

 

[pellicle]

its interesting having this discussion as 1) the makers of the device seem to say that failure to comply with the operational spec of obtaining a sample could result in erraenous readings and 2) just recently there was a discussion about confidence in ability to self test and what was so hard about it and 3) noone seems worried that they are not following the specifications.

I will try to get more details from roche about the impacts of going over 15 seconds.

Perhaps that explains the variance i observed between veinus lab samples and my own home testing.

 

[Protimenow]

I just posted some personal experience/instructions in another thread about the lancet size. I'll probably be repeating some of my suggestions here.

The reason that they want the drop applied within 15 seconds is that their test method requires the first drop of blood - which contains clotting factors that are in the skin when you incise it. Clotting usually starts within fifteen seconds of incision. Later drops are mixed with plasma and other fluids and these meters will provide an inaccurate result if you use them.

(FWIW -- the ProTime meters specifically instruct you to wipe off the first drop of blood. They don't WANT this first drop. They take a bit more blood than CoaguChek XS or InRatio, but may be more accurate because they don't have to factor in the stuff in that 'first drop.' ProTime isn't as easy to use, or as fast, as the other meters, but for those of us who have problems getting that first drop, the ProTime meters may be a good alternative).

When I'm testing with my InRatio, I also do a few of the suggested tricks. (Alere has a good downloadable manual that provides instructions for getting that first drop -- this information would be useful for either the CoaguChek or the InRatio meters and is probably worth downloading). I also don't take it for granted that a drop will form as soon as I incise my finger. I rinse my hand in warm water, I squeeze my knuckle below the fingertip so that a good quantity of blood pools in the tip, and I try to incise in the fleshy part of the fingertip. After incising, I often put pressure under the area of the incision, which usually helps to get the drop out.

(I use the InRatio nearly all the time -- but, after writing about the 15 second problem and prohibition against 'milking' the finger, my ProTime meter seems a bit more attractive than it was before I started writing this. Also -- although my login name is Protimenow, I have no financial interest and no relationship to the company that makes the ProTime meter or supplies or to any of its distributors - this is just a login name that I chose)

 

[newmitral]

Hi pellicle,

I have found a few tricks that help me to get the blood drop onto the test strip quickly. I use an Inratio-2, but the process is pretty much the same.

1. Make sure your hands are warm when you lance the finger. I try to do the test first thing after my morning shower. If not, then run your hands under fairly hot water (but not scalding) to get the blood flowing.

2. Don't "milk" the finger to get the blood out as JimL's suggested. The meter manufacturer folks specifically tell you not to do this because it may result in hemolysis or increase tissue fluid in the blood, which gives inaccurate results for the test.

3. I find that gently and slightly pulling the skin on the finger tip away from the lancing site on each side of the puncture (picture trying to pull open the wound) will increase the initial blood flow to get the first drop out quickly.

Once I started doing these things, particularly #3, I have never had trouble getting a big drop of blood quickly within the 15 seconds allotted.


I'm using the orange 23 gauge lancets with the lancing pen thing set on the deepest setting. So far this is working well for me.
Good luck.

 

[lance]

Pellicle
I have dry eczema on my fingertips and had problems obtaining enough blood in the past. I use the Tenderlett set for 5 with a 21 g lancet now and am successful most of the time. While I was experiencing problems though I'd apply a wet band-aid to the test area the night before testing and that worked. Too much moisture though and the blood sample will smear not form a proper droplet.
Also I puncture more to the top of my finger and apply either to the side of the strip or come from below the strip--it just depends on what would be better.
I know Roche says first drop; however, when I asked my PCP about differences in the first, second or third drop he said it should all be the same and was unaware of clotting factors in the skin itself.
So when I turned XS on and it starts its on-board testing I have been known to puncure the skin and keep wiping that blood away until the timer starts its countdown. The blood is there, it's fresh so why not--that's just me though.
Cheers

 

[dick0236]

I returned to periodic self-testing for the third time, about 4 months ago. Previously, I had used blood draw systems that did not always give a good sample drop. With my new INRatio2 meter, I purchased a box of "Unistik 2 Extra" single use sampling devices (with the orange tab). They work GREAT and have always given a good sample. I can't find a size on the box, but I suspect that they are on the larger size.....but they don't "sting" much.

 

[tom in MO]

I get it done within 15 seconds. I use the countdown timer to make sure. If I don't I restick. In the 180 seconds you can stick yourself at least 3 times to get a good bleed. The time between stick and assay is important, but the 15 second rule is probably on the conservative side. Don't some meters give an error message if the blood isn't fresh enough?

Stick point location is important to me. I put it in the side about 1/4" down from the tip. I now use the smallest guage but at the greatest depth. I wash my hands in hot water until they are warm, dry vigorously. I then put the strip in, hold my hand down at my side (beneath the chair seat) and massage the tip of my middle or ring finger, below the knuckle with my thumb of the same hand. After about 20 seconds (about 10 secs into the countdown) I stick in the side of the finger.

 

[pellicle]

Wow, thanks for all those details. Very helpful everyone



Thanks

 

[Protimenow]

I think that there is a definite reason why some meters only want the 'first' drop, and others say to discard that first drop. The ProTime says to wipe the first drop away. Although a particular clinician may not be aware of it, I believe that there is a high concentration of fibrins in the first drop that aren't there in later drops. Not using the first drop may potentially result in a different value. (It may be interesting for any of our members who somehow wound up with two machines to do parallel testing, using the first drop for one test and a later drop for a subsequent test. Wait -- I have an InRatio and InRatio2. When I get a chance, I'll see if there is any difference).

As I mentioned on some other posts, the ProTime meter is beginning to look a bit more attractive to me, because it doesn't require first drop within fifteen seconds - and because its manufacturer also supplies the Hemochron meters that are used in labs and even in operating rooms to determine a variety of blood factors - including INR. The ProTime 'cuvettes' cost more than the InRatio or CoaguChek XS strips, more blood is needed, and results take longer to get - but the 'fifteen second' rule is not an issue with these meters.

 

[pellicle]

I think that there is a definite reason why some meters only want the 'first' drop,

Clearly!

My first degree at united was biochemistry / microbiology so a lot of this makes sence to me when I hear it

 

[lance]

I agree that I never time myself on that. I'm too busy getting the blood out, which is my job. If the machine is in a prissy mood, it might beep and give me some number, probably 5, that it's taken too long. I try hard to let it not ruin my whole day.

Are you sure #5 refers to too much time or does it mean not enough blood?

 

[Oilman]

Wow, that's a great topic. I just recently had my surgury, but had been using my CoaguChek XS for a couple years now. I do get my drop on the strip within 15 seconds of the lance, but I help with a little squeeze. Didn't realize is said not too. When I purchased my machine London Drug rep had to train me and if you can belief it, encouraged it to get the drop.

Well on a other note just being fresh out of surgery, the coagulation clinic wanted to cross check the machine before trusting its use. I took it to the lab my first three times, first draw was .1 difference, second was .2 difference and yesterday's was bang on the same. So this leaves me alittle confused. But know that all this testing is only a rough estimate and not a perfect science. I will continue as normal. But will check my machine again in a few weeks for piece of mind.

 

[dick0236]

.......... So this leaves me alittle confused. But know that all this testing is only a rough estimate and not a perfect science. I will continue as normal. But will check my machine again in a few weeks for piece of mind.

Anyone who has a few years experience on INR testing or the earlier PT system will agree that it is only an estimate, and often, not even a precise estimate. That's why I have seldom been concerned with the specific number, so long as I am within, or close to, my range of 2.5-3.5......and I really only watch for a trending up or down.

I must go to a lab for testing(Coaguchek XS) once per month because my docs are skeptical of "home testing"....and I need them to renew my warfarin Rx periodicaly. A few months ago, I bought a new machine/strips(INRatio2) on ebay just to check the lab results and to do a few additional weekly tests. I have been testing at home and then going to the lab within the hour for a lab test. My last three monthly HOME/LAB results were: 2.7/2.9...3.4/3.1...3.1/3.1. Personally, I consider these results very close, stable and reassuring.....especially coming from two meter manufacturers. But it also shows that variances of .3 or .4 are standard between meters and also between tests. No need to hit a number, just stay anywhere in your target range.

 

[lance]

I'll try and word this properly forgive me if I don't. There is an allowable range of what's acceptable between the lab result and the monitor result. They use different reagents. (interesting--que and gee are the same).
The difference between .1 and .2 do not alter a dose adjustment--they're too close so don't obsess over the difference. The results are more than a rough estimate--trust them. These test results have been accurate enough to prevent TIA's or worse for both me and my spouse.
Originally both of us took vein draws at the same time we ran our own tests. At the most they differed by .2 and many times they were exactly the same. Then the lab at the hospital closed, vein draw samples are sent to the city and the difference was I think .7. So no more dallying with the vein draw because results like that reflect badly on the monitor, not the lab. Even after all these years of self testing I encounter opposition from the pros--I manage to remain polite when I prefer to give them the third finger salute.
These devices are used world-wide with great success. So happy testing to you.