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MSN,RN,CDE
Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.
Section:  General Diabetes

For the new study published in Diabetes Care, online February 2, 2011 , Dutch researchers had 123 people with diabetes test their blood sugar under various conditions: after thoroughly washing and drying their hands; without handwashing; after handling fruit, which leaves sugar on the fingers; and after washing their fruity fingers.

Overall, the study found that clean hands are key to more accurate results..

Compared with test of clean hands,11% of study participants had test results that were at least 10% off when they tested the first drop of blood from their unwashed hands. The same was true of 4% of study participants when they used the second drop of blood.

The researchers also found that when  study participants tested fruit-exposed hands without washing, 88 percent had blood sugar levels that were at least 10 percent off from their clean-hand readings -- at least when using the first drop of blood. They fared better when using the second drop. But 11 percent still had results that differed substantially from their clean-hand measurements

As for squeezing the finger, the researchers found that too much pressure did appear to interfere with accurate test results. Anywhere from 5 to 13 percent of study participants had a significantly different blood sugar result (versus no squeezing), depending on how much pressure they put on the finger. On average, blood sugar readings were lower when people put pressure on the finger.

 Based on the research findings- good handwashing, testing the first drop of blood and not putting pressure on the finger are important and necessary components of accurate SMBG.

SOURCE: Diabetes Care,online February 2,2011 edition and

http://www.mdecg.com/second-drop-sometimes-ok-for-blood-sugar-testing/

   Thank you. Isabella RN,CDE

MEMBER COMMENTS
Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Thank you Isabella,

 

I've been looking for some information on squeezing the fingers. This is very helpful.

 

EnJOY!

Joy

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Isabella -

Thanks for debriefing us on this important study. Results on studies like this can remind us how important and potentially impacting easy-to-do self-care tips can be on BG control. I venture to guess that many, many people are not washing hands or using the second drop of blood for mroe accurate tests. Trust me, I don't blame people with diabetes for not doing this....any extra step takes time and just puts up another hurdle to get the job done.

 

As educators this research reminds us that we need to reinforce the importance of clean hands for accurate testing. Interestingly this topic was on my mind because I just reviewed an article for our clients that will be in the Summer issue of Diabetic Living. It explains the research you cite and give some practical pointers. It may make for an excellent hand out.

 

Thanks,

Hope Warshaw, MMSc, RD, CDE

Nutrition Section editor 

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.


Joy and Hope, you are most welcome!

I 'm just as taken by the data attached to the squeezing of the finger and the usage of the second drop of blood as you are. So now I'm simply concentrating on telling my patients that thorough handwashing with soap and warm water is the right way to prepare for bs testing , and that it will also improve the blood circulation to the area ...thus increasing the chance of testing that first droplet of blood with more accurate results.. This approach seems to be a win-win for all. Thank you. Isabella RN,CDE

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

thanks for adding my post......    

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.
Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Dr Saraswathi, you are welcome and thank you!

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Thanks for sharing such an important article and topic Isabella!  I really found the fruit exposure hand section interesting.  People take for granted what is on their hands before they test and how it can affect their readings.  Just another reason to stress hand washing, hand washing, hand washing!!!  Thanks!

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

You are welcome, Judy.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

We rarely think about the possible effect unwashed hands can have on our blood sugar levels. Has anyone asked your clients to try an experiment on this? They could test their BG without washing their hands, wash their hands and test again. Often seeing the difference is believing!

What are your thoughts and recommendations on cleaning hands when soap and water aren't available?

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

As a diabetic who struggles to maintain tight control, blood sugar testing is critical.  And this becomes even a real problem as I strive to maintain levels that are consistently within say 70-120 mg/dl on an insulin regime.  It is bad enough that the meters themselves only "claim" +/- 20% accuracy, but other factors can further contaiminate the readings.  I basically wash my hands (well my finger) every time I test.  I try to avoid soaps that contain glycerin and I'll usually use the second drop.  Over time I have discovered that not only will sugar like substances alter readings, but worse, many substances that are soluble in oils and insoluble in water also taint the readings.  For instance, peel an orange and no amount of scrubbing will every get the oils off your fingers, you "must" use a soap.  And these problems are further compounded when we depend upon meters for CGMS calibration.

ps. And I have come to believe that squeezing is a bigger issue when your blood sugar is changing.  Squeezing brings out interstitial fluid which lags blood sugar levels, this is why a CGMS reading lags 15 minutes and you should try to calibrate a CGMS with flat arrow.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Lynn, some people use hand sanitizers if they are not near the sink and are not able to wash their hands. However, I don't know how this particular method of cleaning one's hands affects the bg reading. I do know that usage of an alcohol swab to clean hands results in  a higher reading-just an fyi. Thanks. Isabella RN/CDE

Re: Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.
Quote:

Lynn, some people use hand sanitizers if they are not near the sink and are not able to wash their hands. However, I don't know how this particular method of cleaning one's hands affects the bg reading. I do know that usage of an alcohol swab to clean hands results in  a higher reading-just an fyi. Thanks. Isabella RN/CDE



Most hand sanitizers use glycerin or glycerol to keep from drying your hands.    I avoid them as I believe they taint readings.

ps. Alcohol, if not completely dried will result in a falsely lower reading.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Brian, this comes as an fyi.. I recently attended a Diabetes conference and the lecturer discussed the details of the following study:

http://www.medwire-news.md/57/91310/Diabetes/Hand_washing_may_reduce_false_hyperglycemia_test_results_.html



 As you can see,based on the findings, people who swubbed with alcohol-once or multiple times-the result was not associated with lower readings. Thank you. Isabella RN/CDE

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Several years ago, I did an unofficial study regarding using hand sanitizers to test blood glucose and found the readings to be at least 50mg higher with the hand sanitizers vs washing hands with soap and water.  I always teach patients and the nurses in my classes not to use hand sanitizers to cleanse the area used for blood sample for self monitoring blood glucose.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Thanks for posting the link for that study in Japan.  However, I just read the article and it wasn't the alcohol itself that caused the higher BG result, but the fact that it didn't sufficiently clean the fruit sugar from the fruits they peeled prior to the fingerstick test.  In those controls who did not peel any fruits AND used the alcohol swabs to clean their fingers, the results were the same as those for the individuals who peeled the fruits and  then washed their hands with soap and water.  

I am not familiar with any studies that show that the use of alcohol alone will show falsely elevated BG results if it is allowed to dry (evaporate). 

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Patricia, thanks for your useful input.

Hi Lynda!
 Exactly. The bg levels in both groups-those who washed their hands with soap and water and those who used alcohol swabs to clean their hands after peeling fruit were the same. Nowhere in the article does it say that the bg levels of those who used alcohol swabs were lower.  Also,--an important fyi-none of the subjects in this particular study had diabetes- which shows that if the bg results were effected to this extent in non-diabetics ..then how much more so in true diabetics... Incidentally, if you or any of our colleagues are aware of any reputable studies proving the association between alcohol swab use and lower blood sugar readings-please share!. Thanks very much. Isabella RN/CDE

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Thank you for this valuable information.

Re: Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.
Quote:

Thanks for posting the link for that study in Japan.  However, I just read the article and it wasn't the alcohol itself that caused the higher BG result, but the fact that it didn't sufficiently clean the fruit sugar from the fruits they peeled prior to the fingerstick test.  In those controls who did not peel any fruits AND used the alcohol swabs to clean their fingers, the results were the same as those for the individuals who peeled the fruits and  then washed their hands with soap and water.  

I am not familiar with any studies that show that the use of alcohol alone will show falsely elevated BG results if it is allowed to dry (evaporate). 


I believe isopropyl alcohol is water soluble and although it will loosen oils, it is a poor cleaner.  The effect of alcohol on reagent based testing has been known for quite some time.  One reference is "Effect of alcohol swabbing on capillary blood glucose measurements," which found that "Increasing concentrations of alcohol caused reduction of BG at all glycaemias ..."

The effect is quite easy to observe, simply make a self measurement, dunk your finger in alcohol and retest.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Brian, thank you very much for the link. I read it here:

http://www.practicaldiabetesinternational.com/details/journalArticle/120618/Effect_of_alcohol_swabbing_on_capillary_blood_glucose_measurements_.html


So...the lower bg readings are  associated with increased alcohol concentration after all. Quite an A-ha moment indeed!! Well, washing one's hands with warm H2O and soap and drying of the hands  are all key to accurate bg testing. Thanks again..Isabella RN/CDE

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

If hand sanitizers can throw off the accuracy of the BG reading, what do you recommend to folks who are not near a facility where they can wash their hands with soap and water before testing?  We encourage people to test no matter where they are, and often that's not going to be in a place where they can readily wash their hands.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Lynn, the following is from the source @ the very top of this thread:
" But if soap and water are nowhere to be found, using the “second drop” of blood may be OK, a new study suggests" Thanks. Isabella RN/CDE

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Thanks - and of course I went back and re-read the article, and there was the answer to my question.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

I tell my patients they don't need alcohol swabs, only clean hands, but most of them were taught to use alcohol swabs  and when they go to the doctor that is what they use there so that is where they seem to learn it. 
So is the consensus on using alcohol swabs that if the area cleaned with the alcohol swab is allowed to dry (evaporate) then it is not likely to alter the blood sugar reading?
Thanks.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

Thanks Isabella for reminding us all of the importance of some of these most basic skills.  Especially now that we've entered the hot months, when people are eating Froze Fruit bars, and popsicles, this is imperative.

I had a pregnant patient with gestational diabetes who once called me hysterical because her glucose was 211 mg/dL.  This is someone who didn't need insulin and was diet controlled and had never had a glucose above 135 mg/dL.  She hadn't washed her hands, and had just made a peanut butter and grape jelly sandwich for her three year old son.  After washing her hands, her glucose value was 119 mg/dL.  Here's to grape jelly!  She didn't forget that lesson.

This concept really needs to be stressed to those patients who take insulin and are basing their insulin dose on the glucose value they have just tested, otherwise they are increasing their risk for hypoglycemia.

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

To address Micki's question of,-:"So is the consensus on using alcohol swabs that if the area cleaned with the alcohol swab is allowed to dry (evaporate) then it is not likely to alter the blood sugar reading?"

I asked some of my colleagues + an Endo . Washing the hands with warm water and soap is clearly preferable. But, if necessary-alcohol swabs can be used, however, the patients need to be taught  NOT to test until the area is completely dry.   And Donna, you are welcome Thanks. Isabella RN/CDE

Re: Blood Sugar testing, handwashing, squeezing of the finger and second drop of blood.

We talked about this in a weight loss class I lead for folks with diabetes last week. None of them had ever heard of the recommendation of using the second drop of blood to test when they don't wash their hands. They all had various stories to tell, however, about NOT washing their hands, getting a higher than expected test result, and then realizing they had just handled some type of food, put on hand lotion, etc. It made for an interesting discussion!