Why I Don’t Order Fasting Bloodwork Anymore

This two minute video over on A Country Doctor Talks is getting a lot of attention:

23 Responses to “Why I Don’t Order Fasting Bloodwork Anymore”


  1. 1 meyati April 29, 2021 at 12:04 am

    I need print. I live with a tyrant lab that insisted I that I fast before a lab–I told them –Good-bye- called my doctor and put that in her lap. Same with head scans for head cancer. I’m a survivor.

    I get nauseous if I don’t eat. I had a stomach scan last week, and I have pancreatitis. I’m getting labs for that surgery, and I think that my life should be more comfortable.

    By the way, thank you for taking this stand about fasting, even though I didn’t play the video and don’t know what your points are.

  2. 2 meyati April 29, 2021 at 12:09 am

    Forget the whole thing–I wrote–then it said I wasn’t logged in- then I was logged in I back paged to see if I could copy my comment. I saw all of it, then the good words about you disappeared. Word press sucks right now. Keep up the good work

  3. 3 Thaddeus Buttmunch MD May 8, 2021 at 10:08 pm

    I’ve felt for Years that carbohydrates are the bigger culprit. Cultures that follow the Mediterranean Diet are healthier.

  4. 4 Nalini Naik May 8, 2021 at 10:38 pm

    Why would you not rely on HbA1C?

    • 5 acountrydoctorwrites May 8, 2021 at 10:39 pm

      Because glucose spikes can be many and high before the average goes up and spikes are significant risk factors for all kinds of inflammatory processes including Alzheimer

      • 6 Kurt Rapp, FNP May 9, 2021 at 1:25 am

        Although I certainly agree with many points, I think any bloodwork, fasting or not, is only a snapshot in time and doesn’t reveal all of the information we need to determine health status and habits, or as I like to say “habits and habitus”. Many times when I do DOT exams, drivers spill glucose in their urine, and we of course do a random glucose to get a better idea of why/what degree, etc. When asked, most have just had 2 bottles of soda and some doughnuts just prior. Although these labs, along with an A1C as in this question, help determine health status, I think one of the most helpful tools is a food diary. They are not invasive, anyone can do it, there are many apps to assist if needed, and we can garner more information about the way this person lives rather than the 1 day a year or 2 we may get to see them. It can be reviewed remotely such as by telemedicine, and helps bring a more real teachable moment than explaining labwork to patients. I’m always baffled when I see recommendations from providers with patients who have triglyceridemia to “decrease fats” as many do here, as well, as if that were the culprit…

  5. 7 Don Carr May 8, 2021 at 10:43 pm

    Ditto on eliminating need for fasting. Fasting labs are less revealing. Like looking at a person sitting in a chair and guessing how well they may walk.

  6. 9 Michael S. Cole May 8, 2021 at 10:47 pm

    I stopped asking patients to fast 9 years ago after discovering a Canadian study published in 2012. A total of 209,180 individuals were included in a study which concluded, “Fasting times showed little association with lipid subclass levels in a community-based population, which suggests that fasting for routine lipid levels is largely unnecessary.”
    Sidhu D Naugler C. Fasting time and lipid levels in a community-based population: a cross-sectional study. Arch Intern Med 2012;172:1707–1710.

  7. 10 gdvmdphd May 9, 2021 at 5:51 am

    A1C gives you the chance to detect prediabetes early on; so this explanation is not valid with respect to blood glucose and none of our patients should be eating fruit loops! Having said that, the only other reason to have somewhat fasting (4hrs) is to ensure a realistic value for triglycerides. However, if you over fast you can also get an unusually elevated triglyceride level.

    • 11 acountrydoctorwrites May 9, 2021 at 5:55 am

      I disagree about A1c being so much better than a post breakfast glucose. Spikes are dangerous. And instant oatmeal, Special K and all the other American cereals are just as dangerous!

    • 12 acountrydoctorwrites May 9, 2021 at 6:34 am

      A1c is a late marker: I can fast and dangerously pass other vehicles – or not – on my way to work and still have my trip computer record the same average speed every time. Would that get me out of a speeding ticket??? I don’t think so. Blood glucose spikes are like speeding tickets in our nutritional lives.

    • 13 Gwendolyn Orfan May 9, 2021 at 9:36 am

      As HCP’s we are not assertive enough when discussing the gravity of having early and pre diabetes. Patient’s with lower A1c’s have the most difficulty dealing with post prandial glucose elevations than with basal glucose production and management. Often they have normal or close to normal blood sugars when fasting. As a result we may miss the early stages of diabetes and an opportunity to change the course of the patient’s disease progression.

  8. 15 Hank Lubin, MD May 9, 2021 at 7:46 am

    I have told patients NOT to fast for many years. Better to pick up an otherwise undetected early diabetic than see a higher TG. You can always repeat the lipids fasting if needed, but if you miss the early DM, it will often be 1-2 years before the patient is back for routine labs again. Early DM (given the bogus name PRE-DM – nothing PRE about it, just not bad enough to put on meds) is most successfully treated if diagnosed early. As a result, almost none of my DM2 patients wind up on insulin, even after decades, and my average A1c across all my diabetics is <6.5. No renal failure, no significant retinopathy, no amputations. It is worth it to detect DM early, even at the cost of a few repeat lipid panels.

  9. 17 Emma Groethe, CNP May 9, 2021 at 8:29 am

    I appreciate Dr. Lubin’s reply. So many patients I see with obvious prediabetes have been told by their physician that they have a normal blood sugar. Prediabetes onset is on average 11 years before diabetes and your blood sugar can look normal. Why? too much insulin. The pancreas is trying to keep up with the high sugar load and people eat more in response to lower blood sugar caused by overproduction of insulin which causes more insulin to surge and so on. Americans get bigger and bigger because high insulin levels cause weight gain so they eat more and we keep growing and growing. Toddlers snack all the time on goldfish or other high carb snacks.
    Americans don’t just eat out for dinner, they eat out for breakfast, lunch and dinner and between meal snacks, constantly feeding high insulin levels in response to insulin resistance. By the end of 11 years years of prediabetes, the pancreas is at 50% capacity and you are diabetic with effects on major organs and blood vessels already longstanding. I tell patients insulin resistance is the real issue. Cut carbs, exercise (the 2nd major factor because exercise helps tissues use the insulin thus cutting down on the production and of course as a society we are not exercising) maintain a normal weight, eat healthy fats and proteins. Type II diabetes for most is a genetic predisposition expressed by lifestyle. Lifestyle IS THE KEY.

  10. 19 Gregory Kosters May 9, 2021 at 4:26 pm

    Hmmm….. treating the patient, or treating the patient’s blood work?
    If someone has a fam Hx of diabetes, has a BMI over 30 and elevated triglycerides, you know what you need to do as a physician whether the LDL is accurate or not, whether the fasting or postprandial blood sugar is off or not.

  11. 20 Netley DSouza, MD May 10, 2021 at 2:47 am

    Fasting makes the labs good on paper (or computers now), but is not truly reflective of what patients are doing during their waking hours, ie eating, drinking, snacking etc. I would rather know the true daily reflection of their sugars and triglycerides.

  12. 21 Connie Lane, MD May 10, 2021 at 9:55 am

    Sadly, making “labs good on paper (or computers now)” is a fundamental mandate in today’s pooled data driven medical system.

  13. 22 Anthony Musci, MD May 10, 2021 at 1:28 pm

    Interesting conjecture that begs for some clinical outcomes and cost effectiveness research.

  14. 23 Gus May 11, 2021 at 8:09 pm

    I think you are absolutely correct in your theory. You are getting false numbers when the patient fasts and then gets blood drawn,you can actually miss the patient who is pre-diabetic, and with diabetes at a epidemic level with fasting a lot of patients might not find out until its too late. I wish more doctors followed you correct analysis of fasting vs. Non-fasting. I am a retired physician who completed a residency in both Internal medicine and anesthesia and you couldn’t have said it more eloquently.


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