Why is my finger stick glucose often different that a laboratory glucose test ?

Why is my finger stick often different that the laboratory glucose test?

Is there a difference between whole blood and plasma glucose test results ?

   We all put a lot of faith in our home glucose testing equipment and feel comfortable making management decisions based on the test results.  However, have you ever wondered why your finger stick capillary test is often different than the venous glucose test done in a laboratory. There are a number of variables effecting your glucose test results.

   The source of the blood sample ( arterial , capillary  or venous ) and how the blood was processed all make a difference .  Whole blood is usually removed from a vein in our arm and then put into a centrifuge and separated into plasma and red blood cells. The glucose test is then done on the plasma component of the blood. Whole blood can also be allowed to clot which separates the blood into red blood cells and serum.  Your finger stick test is measuring whole blood glucose taken from capillaries in your finger and done on a machine with it's own built in error rate. The last time I checked, meters  are  required to have an error rate of < 20% at glucose levels of 30 to 400 mg/dl.

 From my own personal experience in the hospital and office , where I frequently compared finger stick results with hospital lab. results , I believe the error rate on most meters is small and not a major issue.

The source of the blood effects the results. Arterial blood is about 5% higher than capillary blood and 10% higher than venous blood. You are not likely to be using arterial blood but you will be comparing capillary blood ( finger stick sample) to venous blood that is usually taken from your arm by a lab. Tech. This means ,that if you did a fingerstick test( capillary blood )at the same time as a laboratory test( venous blood) , your result may be a little higher than the lab result by about 5%
Their is another interesting variable to be aware of. Your glucose meter reads” whole blood ” which is about 10 to 15 % lower than “plasma ” used by the lab .. I believed that this was a good thing when I was following hospital patients on continuous intravenous insulin infusion because the hourly finger stick test were a little higher ( capillary whole blood) and made the lab ( venous plasma )and bedside test have a little better correlation .Then the meter builders decide to convert the whole blood results into a plasma-calibrated result. For the doctor this change resulted in higher bedside result and more concern that we may miss low test results.. I had to adapt to the change.
Summary:
So this is probable a lot more than you wanted to know but it may help you understand why your home test may not match the lab. results. In general our home meter are wonderful machines that have dramatically improve our lives..

Have fun , Be smart and test your blood glucose frequently and learn how to use the results to make decisions in in your daily diabetes management decisions.
David Calder, MD

Tips for converting A1c reading to average plasma glucose

 Answer to yesterdays question - 

        An A1c test result of 8  is equivalent to a mean glucose of 183 mg/dl or 10.2 mm/l 

  A1c interpretation tip -

       A 1 point change in your A1c equals a 29 mg/dl or 1.6 mm/l  change in your average glucose.  I

       personally remember the desirable target goal for A1c is 7 which equals 154 Mg /dl ( 8.6 mm/l )

       and the add or subtract  from there. There are calculators that are useful if you happen to have

       it with you at the time. The attached link is to the ADA calculator.

       http://professional.diabetes.org/glucosecalculator.aspx

   I have attached a link to an article with more details on this 

   subject.

   http://care.diabetesjournals.org/content/early/2008/06/07/dc08-0545.f   ull.pdf

  
 What are the Benefits of A1c testing ?

 Glucose in blood binds to  hemoglobin in  red blood cells  and remains attached for the life of the  cell which is about  3 months.  Higher glucose levels are associated with more glucose attachment . The chart below will give you an idea of how A1c results correlate with mean glucose test results.. The chart below was copied from the American Diabetes Association Standards of care
  
     A1C (%)                  Average plasma glucose


                                          mg/dl               mmol/l

        6                                  126                     7.0

        7                                  154                     8.6

        8                                  183                    10.2

        9                                  212                    11.8

       10                                 240                    13.4

       11                                 269                    14.9

       12                                 298                    16.5

          

    The A1c test is a predictor of the risk for developing diabetes complications. Two classic studies, the DCCT study in Type 1 Diabetes and  the UKPDS  done with Type 2 Diabetes demonstrated a significant   reduction in eye , nerve and kidney damage by reducing  the A1c  to 7. There was about a 30 % reduction in risk for  a 1 % point drop in A1c. There was also a nonsignificant 16% reduction in cardiovascular risk  by reducing The A1c from 8 to 7 in the UKPDS .

 These two large studies  and another one called the Kumamoto study provided the evidence for establishing an A1c result of < 7 as the recommended target goal









Have fun , Be smart and know your numbers

David calder,MD

Question - What is the difference between whole blood and plasma glucose test results ?

Question - Define glucose sensitive insulin release .

    Yesterdays questions:

    Define glucose sensitive insulin release. 

       Non- Diabetic:

           Beta cells in the pancreas normally respond to any increase in blood glucose levels with an 

           initial burst of insulin( first phase insulin release that begins with in 2 minutes of food intake) 

           followed by more sustained insulin release ( second phase insulin release ) as needed to

          maintain glucose levels in a normal range.    

       Type 2 Diabetes: 

           The decline of insulin sensitivity to increasing glucose levels occurs very early in the 

           development of type 2 diabetes and is an early marker of Beta cell dysfunction. 

        Significance :

             Sulfonylureas drugs and meglitinides* stimulate beta cells to release insulin with no 

             regard for blood glucose levels which increases the risk of hypoglycemia.

             Some of the newer medications such as GLP-agonist and DPP-4 inhibitors ** restore

             and preserve beta cells ability to release insulin when stimulated by a meal time

             increase in glucose levels. This reduces the risk of hypoglycemia.

       Summary:

             Sulfonylurea type medications produce a continuous unregulated insulin release

             irrespective of a person glucose level and increases the risk of low blood sugars.

             GLP-Agonist and DPP-4 inhibitors produce meal stimulated insulin release and 

             reduce the risk of hypoglycemia               

            *Amaryl ( glimepiride ) , Glucatrol ( glipizide ) , Diabeta ( glyburide ) and others.

             Meglitinides - Starlex (nateglinides ) , Prandin (repaglinide )

          ** Byetta ( exenatide ) , Victroza ( liraglutide )

             Januvia ( sitagliptin ) ,Onglyza ( saxagliptin ) , Tradjenta ( linagliptin ) , Nesina ( alogliptin )

        Where is glucagon made and what does it do ? Hint . Click on the link below.

        Glucagon effects your life every day

    New question -  An A1c test result of 8  is equivalent to a mean glucose of_____ . 

        A little tip for  interpreting your A1c results will be revealed tomorrow.

Have fun , Be Smart and reduce your risk of hypoglycemia
David Calder,MD

Lantus insulin and Byetta is a good combination

                                      Lantus insulin (glargine ) and Byetta ( exenatide ) 

                     This is a very useful combination for people with Type 2 Diabetes

 Lantus is very effective for providing basal insulin and controlling fasting glucose levels.

 Byetta is an excellent choice for controlling the daytime glucose levels

  Byetta allows for glucose sensitive insulin release which reduces the risk  of hypoglycemia

    Byetta slow gastric emptying

    Byetta helps regulate dysfunctional glucagon secretion

    Byetta often helps with weight loss

 Two very good medicines  made better in combination.

  Have fun, Be Smart and talk to your doctor about treatment options

  David Calder,MD 

Questions for tomorrow

     Define glucose sensitive insulin release.  

     Where is glucagon made and what does it do ? Hint . Click on the link below.

     Glucagon effects your life every day

-------------------------------------------------------------

Type 2 Diabetes , pills not working.Is there option other than insulin ? Maybe

This is an interesting article that opens the door to another treatment option for patients with type 2 diabetes who are considering starting insulin. This study compared the effectiveness of once weekly exenitide 2mg ( GLP-1 Agonist , Bydureon ) to once daily Lantus insulin (Glargine).

Baseline patient characteristic :
                 Bydureon ( exenitide ) 2mg                   Glargine ( Lantus insulin  starting dose 4 units )
 Number              215  patients                                         212 patients          
 Mean age             57                                                          56
 Mean weight       69.9 kg                                                   71 kg
 Mean A1c             8.5                                                           8.5

Results at 26 weeks of treatment :
A1c < 7                 89 of 211 patients ( 42% )                        44 of 210 patients  ( 21% )
A1c <6.5               44 of 214 patients (20.6% )                        9 of 212  patients (4.2 %) 
Weight reduced     yes                                                               no             

Clin Ther. 2012 Sep;34(9):1892-908.e1. doi: 10.1016/j.clinthera.2012.07.007. Epub 2012 Aug 9

Efficacy and safety profile of exenatide once weekly compared with insulin once daily in Japanese patients with type 2 diabetes treated with oral antidiabetes drug(s): results from a 26-week, randomized, open-label, parallel-group, multicenter, noninferiority study.

Inagaki N, Atsumi Y, Oura T, Saito H, Imaoka T.

Source

Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Have fun , Be  Smart and discuss all options with your doctor
David Calder, MD

please review these post for more information on Bydureon ( exenitide ) and Lantus insulin

1. Diabetes medication , the first choice is easy, th...
2. New Diabetes Meds= High Cost ! Hypoglycemia to the...
3. New Medications- High Cost- Hypoglycemia to the Re...
4. Glucagon effects your life every day
5. Bydureon is my first choice for a second medicatio...
6. Glucophage "failed " Now what should I do ?
7. Good news. A once a week diabetes injectio
8.  Preserve your Beta Cells, Its hard to find new one...
9.  DPP-4 inhibitors vs sulfonylureas

         

The ideal patient. Is there one?

On May 17th Doctor Calder wrote about a study that was done and he outlines the findings for you with one caveat.

He states..."Looking at the data in studies like this does does not show the full picture of the long term diabetes management . It is easy to set and achieve ideal target goals for A1c , blood pressure and the other 7 risk factors in the ideal patient. Unfortunately many of us do not fall into that category . Age , general life situation and medication cost play an important role in trying to achieve ideal diabetes management. One size  certainly does not fit all . It is important to remember , test result that are perfect for your neighbor may not be the best one for you."

Now I can tell you from my own perspective I am far from the ideal patient. I believe the Doc will agree with me knowing me the way I am. I have a hard time sticking to a diet. I have a hard time dealing with stress and to be honest all of these factors create and control my blood glucose and my heart. 

One minute I am perfect and then a little stress hits and BOOM my blood glucose flies high or low, just depending.

I use to post a picture of the DNA of diabetes and ask people, "when you do to your Doctor does he or she see this picture or your face?" I asked this because many Doctors, but of course not all look at us as books. They hear us, they try to listen and then they go to the book and they prescribe. The thing is they really don't hear us, they hear words and see numbers and then make a decision. No consultation no nothing.

Then on the other side once they begin to speak to us, how many of us actually understand what they are saying? They have a language all their own just like we are not a book. They speak to us we listen but do we truly understand? Do we really know what they have planned or do we just go out the door take the meds prescribed and go on with life till we see them again?

This scenario is more real than one may think. I happen to have an Internist who believes in listening to me and I do to her. We argue, we discuss, we develop a plan of attack when my numbers, like my A1C are out of whack and then we go to it. The thing is we understand each other and we listen to each other.

Doctor Calder wrote a book "The Diabetes Office Visit" ( get a copy if you haven't) that really help you to understand what your Doctor is saying and how you can speak to your Doctor so they can help you. Amazing book. The perfect guide for both Doctor and patient. In fact I gave a copy to my Internist and maybe that's why we have a great relationship. 

In closing what must be remembered is there is no ideal patient. I don't care what someone says. At some point in their life they were not ideal. So don't let people or Doctors intimidate you by telling you your not ideal. No one is! 

Be well

Mark

I believe , the key to success in a persons diabetes care is ____?____ .

I will review some of the abstracts from the recent American Association of Clinical Endocrinologists annual meeting over the next week.
#1

BARRIERS TO INSULIN INITIATION IN TYPE 2
DIABETES MELLITUS - A SINGLE INSTITUTION
STUDY AMONG THE PHYSICIANS
Kelly Khai Li Yap, M.D., Yiyi Yan, Aruna Chelliah
York Hospital

The study included 1226 patients with Type 2 Diabetes with 273 with  A1c results  greater than 8.5%. Among these 273 patients , 119 were not on insulin. A survey was conducted among the primary care physicians treating these patients to investigate the barriers insulin initiation .

Results;
 45 % of the physicians responded
 80 % of the responding physicians believed insulin was efficacious
 90 % disagreed that insulin should be started by a endocrinologist
 66 % chose to delay insulin therapy because it was to burdensome for their patients
 60 % said that insulin therapy was to complicated for their patients and more than 50% said the variety
          of insulin products lead to confusion.

Conclusion:
" Our study suggests that education is the key to improving glycemic control and insulin usage among
   patients managed by their PCPs."


My opinion:
   Type 2 diabetes is a progressive disease leading to insulin deficiency and the need for insulin replacement . The convenience of oral diabetes medication and the increase complexity and risk of hypoglycemia with insulin is certainly a big factor  in delaying insulin use . Also , many people on insulin still do not  reach recommended target goals . A good example is , this study, 56%  of  patients  were on insulin and  still had  an A1c greater than 8.5 % in order to qualify for this survey.

   Looking at the data in studies like this does does not show the full picture of the long term diabetes management . It is easy to set and achieve ideal target goals for A1c , blood pressure and the other 7 risk factors in the ideal patient. Unfortunately many of us do not fall into that category . Age , general life situation and medication cost play an important role in trying to achieve ideal diabetes management. One size  certainly does not fit all . It is important to remember , test result that are perfect for your neighbor may not be the best one for you.

   The  above problems in diabetes management  was one of the main reason for me writing ,  Diabetes Office Visit  and developing this web site . I believe , the key to success in a persons diabetes care is a well informed patient wanting to preserve their good health  blended with the knowledge and wisdom of their health care provider .  Setting , reaching and maintaining target goals in diabetes care is the secret to maintaining good health.

Know your treatment goals:
  The informed patient knows the American Diabetes Association  recommended goals and their 
  health care provider has the wisdom to help fit those goals into his / her individual life situation.

Ask for a copy of your laboratory test results.

Knowing your treatment goals simplifies your health care
    If your laboratory or exam result is not at  the mutually agreed goal .

  Ask a simple question.
    Doc. ( or other health provider ) , my test is not at our mutually agreed upon goal .

  Can you help me fix it ?

Have fun , Be Smart and Check out the Diabetes Office Visit video above.
David Calder , MD

Related post for your review:
Diabetes is a game that allows you to be less than...
Fixing The 9 ,prevents heart disease and amputatio...
Diabetes Office Visit Simplifies Diabetes Care

A little advertisement
You can find all of the tools to improve your diabetes care in , Diabetes Office Visit . Available in paper back , iphone and ipad apps.

Diabetes Medication and Cancer

After reading the Doc's post today I sat back and thought about the number of meds I take right now that have been linked to cancer without real proof as the Doc has said.

Here is the link to his May 3rd post:
http://www.diabetesofficevisit.com/2013/05/diabetes-medications-and-cancer-is.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A

Now let's think about this for a second. I know that everything in this day and age has been accused of causing cancer. I mean there isn't one thing that hasn't been linked so to say these drugs are linked to cancer is the norm as far as I am concerned.

If I don't get proof or positives results from a study then guess what, it's just another unconfirmed cancer scare, which to be honest I am sick of.

They tell us to take these drugs then all of a sudden they mention cancer and everyone is ready to stop these drugs that are keeping us alive.

How many of you out there taking some of these diabetes drugs notice a better lifestyle while you are one them? How did you feel before or how do you feel when you don't take them?

I've had issues where my insurance denies a new med and I wait for ages to get it approved and once it is approved I feel fantastic. Then there is always a point when I run out and the pharmacy needs to get approved for the next refill and I go without for a few days and go back to feeling like crap.

Now whether they are going to give me cancer or not I'm not worrying unless there is some positive proof and the Doctor says get off this stuff now. Haven't heard that yet.

In fact the only drug my Doctor took me off and that was because I did my research was Actos and that had proven to cause issues with the heart and retaining fluids. Once off I lost weight and felt great.

I've been a diabetic for 5 years, have been taking Lantus, Humalog, Januvia, Metformin and I don't have cancer nor have I any symptoms. So guess what I am going along with life and feeling great because of these meds for now. If something comes in the future then I will figure out what to do. Till then I am living life to the fullest.

I like this quote

I like this quote :

"	Not everything that is faced can be changed. But nothing can be changed until it is faced." -- James Baldwin, American novelist, essayist, playwright and poet

 My other favorite quotes :

My mom ,  " Columbus took a chance " 
                   " hard work and persistance is the secrete to success "
                   " An idle mind is the devils workshop "

My dad , Big John " I will die with my boots on" and he did with a shot of his favorite Jim Bean whiskey

Wayne Gretzky , " You miss 100% of the shots you don't take". 

Have fun , Be Smart and be happy
David Calder,MD

Diabetes medications and cancer is complex and the lack of confirmed data leads to uncertainties.

The relationship between diabetes , diabetes medications and cancer is  complex and the lack of confirmed data leads to uncertainties. I have attached links to 2 previous post and timely comments that you may want to review before reading todays post.
The comments reflect the concerns each of us may have as we take our diabetes medications each day.

 Diabetes, Januvia and Cancer
 Diabetes and Pancreatic Cancer . No simple answer... 



 Certainties:

  Good
  metformin ( glucophage) reduces the risk of Cancer

   Not so good
   - Type 2 diabetes increases cancer risk. Diabetes seems to be linked to a variety of cancers including
      breast, hepatic , colon and pancreatic
    - Pioglitizone  ACTOS) increases the risk of bladder cancer
    - obesity increases cancer risk
    - smoking increases cancer risk
    - just being alive increases cancer risk
    - family history

   Uncertainties , My opinion .
     - Most of the studies have come from the volunteer reporting of adverse events to the FDA and
       similar organizations and most physicians are not reliable reporters of this type of information. 
       The other study listed below raises the question. Did the slow development of pancreatic cancer
       and  silent pancreatic damage over 10 years cause the diabetes ?

           "On the other hand, some studies demonstrated that because of underreporting , only 5%–10%
           of serious adverse reactions can be detected by spontaneous reporting systems. Whether 
           similar underreporting exists with respect to incretin-based therapies is unclear.
           Analysis of spontaneous reports does not allow adjustment for known  risk factors for 
           pancreatic cancer such as obesity, smoking, family history, or chronic pancreatitis, even if this 
            information is available."

           "Might GLP-1–based therapies induce or promote pancreatic cancer? 
          Recent studies suggested that the time  between tumor induction, tumor development, and
          metastasis/clinical diagnosis is >10 years. The German cases were individually assessed and
          the exposure time to exenatide was consistently found to be short (2–33  months). 
          Thus, given that exenatide and liraglutide have been on the market for <10 years, there is 
          considerable  doubt that exenatide induces tumor development. If the suspected 
          relationship exists, exenatide is likely to  promote tumor progression rather than initiation, 
          which corresponds with data showing that  exenatide promotes  pancreatic ductal 
          hyperplasia. 
                            "GLP-1–Based Therapies: The Dilemma of Uncertainty  
                              Gastroenterology   Volume 141, Issue 1 , Pages 20-23, July 2011
                              Joachim Spranger   Ursula Gundert–Remy, Thomas Stammschulte

                             Department of Endocrinology, Diabetes and Nutrition, Charité-  Universitätsmedizin Berlin and Drug Commission of the German Medic                                      

                              al Association, Berlin, Germany 

       
    -  "Diabetes or impaired glucose tolerance is present in 2/3rds. of pancreatic cancer patients "
           New onset diabetes in people over age 50 have a higher risk of pancreatic cancer.
                                Minerva Gastroenterol Dietol. 2012 Dec;58(4):331-45.

                                Diabetes and pancreatic cancer.

                                Muniraj T, Chari 

                                Yale University School of Medicine, New Haven, CT, USA.


I have attached a copy and paste link to an American Diabetes Association article reviewing their views on this topic.

http://www.diabetes.org/for-media/2010/experts-explore-emerging-evidence-linking-diabetes-and-cancer.html

Have fun  , Be Smart and talk to your doctor before stopping your diabetes medications
David Calder, MD

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