Rookie Mistake, I think I got this home testing figured out

[hook]

The trainer who showed me how to pull up my blood told me the machine would show an error if I bumped the strip. Well, this disturbed me since you have to touch the dang thing to get your blood to wick into the strip.

The first strip worked fine, and the next five showed an error. She said I was bumping the strip. After I inspected the strips I noticed the ones that showed an error did not have blood wicked to the sweet spot on the strip where the blood is measured.

Long story short the lady watched me wipe my finger with with a wet towel. I figured out the moisture on my finger was causing the blood to spread rather than making a nice dome.

I wiped my finger dry, and the last test went fine.

Moral to story, test with a dry finger.:thumbup:

 

[Luana]

The trainer who showed me how to pull up my blood told me the machine would show an error if I bumped the strip. Well, this disturbed me since you have to touch the dang thing to get your blood to wick into the strip.

The first strip worked fine, and the next five showed an error. She said I was bumping the strip. After I inspected the strips I noticed the ones that showed an error did not have blood wicked to the sweet spot on the strip where the blood is measured.

Long story short the lady watched me wipe my finger with with a wet towel. I figured out the moisture on my finger was causing the blood to spread rather than making a nice dome.

I wiped my finger dry, and the last test went fine.

Moral to story, test with a dry finger.:thumbup:

I'm sure that wiping you finger dry did solve the problem; however, I think you might have defeated the whole purpose of the wet towel (which was probably alcohol?) and got germs back on your finger, which may possibly interfere with a reading (with glucose meters, sometimes testing with a finger that's not clean can yield an inaccurate result). I would use hand sanitizer. It dries pretty quickly so you'll be able to get it on the strip well. I'm diabetic, and that's what I do before testing.

 

[ALCapshaw2]

The recommended procedure is to wipe your finger with an Alcohol Wipe then AIR Dry before sticking.

 

[hook]

I was wiping with a damp paper towel,,, water only. She should have known better. I agree, the alchohol wipes work the best. I grab a few every time I go to the doctor.

 

[Cris N]

Oh, you're supposed to test with a clean finger??? Oops.:rolleyes2:

 

[Philip B]

Error?

Error?

Just do a stick which produces a nice hanging drop of blood. The blood is the only thing that touches the strip reservoir. I usually swing my arm in a circle after doing the alcohol wipe thing to speed up the drying process, it also insures that I've got a good amount of blood in my finger(s).

-Philip

 

[Bina]

My machine specifies that alcohol is not necessary. I wash hands with warm water and soap, rinse well, and dry well with clean towel.
Stick the finger, get a nice hanging drop of blood and hold it beside the test strip, it will be drawn into the strip.
Good for you, home testing rocks !!

 

[Protimenow]

What may be more of a mistake is not reading the instructions for your meter. You don't say which meter you are using. You say that you wipe off the first drop of blood.

For the CoaguChek S, they WANT that first drop of blood. The instructions say so. If you wipe it away, you may be winding up with a higher result than if you didn't.

I now have a CoaguChek S, and a ProTime 3. The ProTime doesn't want that first drop - the CoaguChek DOES. When I occasionally simultaneously compare both meters (and I haven't yet), my plan is to put the strips into both testers at almost the same time - to wait till they ask for blood, to incise my finger with the ProTime Tenderlette, and put that first drop on the CoaguChek strip, then put the rest in the Tenderlette cup, and run the test on that.

The point here is that, other than 'rookie mistake', we should all - anyone who does self-testing - read the instructions and be sure of whether or not they want the first drop - and how much time they give you after you puncture your finger until you put the blood on the strip. (CoaguChek wants the blood drop within fifteen seconds of puncture)

 

[Freddie]

FYI - the Coaguchek XS monitor allows over a minute to get that first drop onto the test strip.

 

[Protimenow]

Since I'm not using the XS, I didn't check that data. It's good to know. It's another reason for some to consider upgrading to XS, in addition to saving those poor rabbits who donate their brain thromboplastin so that we arrogant humans can test our own blood.

One thing that may be somewhat confusing for new users is the countdown timer -- they may think that the timer, which is telling them how much time they have left before the strip expires - is actually teling how much time is left to get the drop of blood onto the strip. (Wouldn't it be nice if the meters said, somewhere on the front, that they want the FIRST DROP, and it should be put on the strip within 15 (or 60) seconds of puncture?)

The InRatio no doubt has a similar time limit for the drop of blood, and I'm not sure if it's first drop or blood after the first is wiped away. Home testers (and medical professionals) should be aware of these requirements - but sometimes aren't.

 

[Bina]

FYI - the Coaguchek XS monitor allows over a minute to get that first drop onto the test strip.

You get one minute to do the whole step of: lancing and dropping of blood onto test strip.
But the actual drop of blood should be on the strip within about 15 seconds of it showing up on your finger.

 

[Protimenow]

Hmmm -- the CoaguChek S gives you more time to lance and drop the blood. Perhaps users didn't understand this and were taking too long to drop the blood, so they shortened the allowed wait time. Fifteen seconds to puncture then aim at the the little light under the strip can seem like an awfully short time.

(I still don't think it's a bad idea to put something on the meters saying that the first drop after puncture must be received within 15 seconds of puncture)

 

[lance]

First drop, second drop?????????????????

The level of anticoagulant is the same throughout our body and I've never understood why there would be a difference. Venous blood, capilliary blood--it's all blood from the same person.

Protime now--I think you are making things difficult for yourself and the "S" can cause that.
Regards

 

[Protimenow]

Actually there IS a difference between first drop and later drops. The first drop usually clots faster than subsequent drops -- although it's still the same blood, there are more clotting factors in the first drop of blood (and you're probably getting traces of epithelial cells that are part of that first drop) than in the other drops of blood. After a bit of research, it looks as if it's the platelets that are more highly concentrated in that first drop of blood that cause the wound to close more quickly than later drops that have fewer platelets. This is the reason why testers like the CoaguChek S (and probably other meters) WANT that first drop, and testers like ProTime say to wipe it away.

If there was no difference, the makers of these testers would not be so specific about first drop or no first drop.

No, I'm not making it too hard on myself -- I'm just trying to be assured that the tests are consistent and accurate - and according to device manufacturer instructions.

(FWIW - venous blood requires different handling, too --- if you're using venous blood for testing with a meter, it must go into a plain plastic tube. Put it into glass and it starts clotting right away. The glass collection tubes designed for prothrombin testing have a chemical in them that lets them store the blood without clotting. How the blood is handled can make a big difference)

 

[lance]

I still don't "get it".

 

[Bina]

Lance, would you be so kind as to go to your barn and give your ponies a BIG KISS from me.
Time well spent.
Thanks. ;-)

 

[Protimenow]

Lance:

Nature has made us so that the parts of our body that are most likely to get cut (such as fingers) have other clotting factors besides just those that anticoagulation impacts, located in and just under the skin. The blood further inside the body - and the second and later drops of blood - don't have those factors in such high concentrations. The platelets, near the surface of the incision, are there to close the wound quickly. Their function is not related to levels of warfarin in the blood. Because platelets are so important to the clotting of this first drop of blood, and start the clotting very soon after the incision, the meter manufacturers either want the blood within fifteen seconds of making the incision, or don't want first drop at all. The lower concentration of platelets in later drops of blood mean that this blood coagulates less quickly, and the coagulation test shows more of the influence of warfarin in the blood and less of the effect of platelets. CoaguChek and, I think, InRatio factor in the effect of platelets in the first drop of blood -- using a second or later drop of blood with these meters may result in a measurement of a higher INR than actually exists. Similarly, using the first drop, along with some subsequent drops needed to fill the collection cup for ProTime may result in an artificially LOW INR.

You may notice, if you get an accidental cut, that if it doesn't close right away, it may bleed for quite a while. This is because those factors that help a small cut close up quickly have bled out, and the blood without those factors is now bleeding.

I've noticed that, using a 21 gauge lancet, I can get a drop of blood for my CoaguChek S meter, and the hole closes up quickly, almost as if there was no cut at all. I've noticed that if I push blood through the lanced hole, it takes a lot longer to close up. Next time you test your blood, you can certainly validate this -- if you're using a meter that takes the first drop, put that drop on the strip and see how quickly the wound closes. The next time, give it the first drop, and them squeeze some more blood out (onto a paper towel, or somewhere), and see how much longer it takes to close.

I hope this clarifies the issue of WHY there's a difference between first drop and later drops.

 

[ShezaGirlie]

I have a CoaguChek XS and it requires the first drop..!

 

[Protimenow]

I think most of them DO.
The ProTime, by contrast, says to wipe off that first drop -- it tests the blood that's more representative of what you get in a venous blood draw.

I suspect that the people who designed the system for CoaguChek (and maybe also InRatio) probably figured that taking the first drop is less painful and easier than wiping away a drop and then trying to squeeze out another one. Their meters probably COULD HAVE used blood drawn later, but the results may be different if anything other than first drop was tested. They may have created a bit of confusion by not being as specific about first drop (a recommendation printed on their meters, for example), than they could have been.

I am assuming that the INR for a first drop is probably lower than one for later drops of blood. (That first drop starts clotting very quickly -- that's why CoaguChek wants the drop within fifteen seconds of incising your finger). If you don't use the first drop, you may be getting a higher INR value than you should be.

 

[Bina]

Janie, how is your cat doing ?