You Don’t Need Fasting Labs

If you are a prison doc, I am about to solve one of your vexing nuisances, so pay attention.

The vexing nuisance is trying to get fasting labs.  In the outside world, having patients fast before drawing blood work is not too much of a problem.  The patient just goes in for the bloodwork at their convenience, without an appointment, in the morning before they eat breakfast.  They then can eat right afterwards.  They actually miss no meals—they just delay one.  The patient is in charge of the process. 

Things are different in a prison.  The blood draw has to be scheduled in the medical clinic.  The prison patient has to remember the appointment and also not to eat breakfast that morning.  If they forget and eat breakfast, well; the blood draw must be rescheduled. Plus, there is no food make-up for the prison inmate.  Once they miss breakfast, they have missed breakfast.  This patient might have to miss lunch, too, if the scheduled blood draw is delayed for some reason.  Predictably, these blood draws are not popular with inmate patients, which leads to more “I forgot not to eat.”

There is a substantial cost to the medical team in time and effort in scheduling these fasting blood draws, reminding the patients not to eat and then rescheduling the substantial number who forget and ate breakfast. I have seen frustration levels in the medical staff reach the breaking point when patient after patient shows up for their routine blood work non-fasting.  “It’s like this every time!” I am told.

What are we to do? Everyone says that patients have to be fasting to get accurate lipid levels.

Science to the rescue!  Recently, the following paper was published in JAMA:

Association of Nonfasting vs Fasting Lipid Levels with Risk of Major Coronary Events in the Anglo-Scandinavian Cardiac Outcomes Trial—Lipid Lowering Arm.  JAMA Intern Med. 2019;179(7):898-905.

As with most scientific medical papers, the title is horrible.  It does not tell you what the paper is all about. This paper compared fasting lipid levels versus nonfasting lipid levels in 8270 patients and found:

Measurement of nonfasting and fasting lipid levels yields similar results.”

Memorize this quote!  Tell everybody you know! The article encourages all primary clinicians to “measure lipid levels without required fasting.”

And it is not just this one study.  There is a robust body of evidence (referenced in this article) that says the same thing:  You do NOT have to make patients fast to get accurate lipid levels.  Fasting or nonfasting—it makes no difference. 

Using nonfasting lipid levels is even supported by the 2018 CC/AHA cholesterol guidelines.

So, if your facility is still requiring patients to skip meals before routine blood draws, stop!  Take this article to your Therapeutics Committee if you have to and make your life and the lives of your patients so very much easier!

As always, what I have written here is my opinion, based on my training, experience and research. I could be wrong! If you think I am wrong, please say why in comments!

A version of this article was originally published in CorrDocs, a publication of the American College of Correctional Physicians.

5 thoughts on “You Don’t Need Fasting Labs

  1. Charles Lee

    Excellent, Jeff, as usual. I’ve been to facilities where breakfast is very early, 4:30 am at one. This would really be of value in institutions like this.
    What about Fasting blood sugars? Other than getting A1C’s , anything about this? Or can we just do without them.

    Reply
    1. Jeffrey Keller MD Post author

      Thanks, Charles! There is also no need for fasting blood sugars, in my opinion. If you are using the fasting blood sugar as a screening test for diabetes, it is more accurate to get an A1C, which does not have to be fasting.

      Reply
  2. Sandra

    Hello! Tks for your posts, they do help me as a new nurse practitioner working in a prison.
    Can you give me an example of labs you usually ordered for annual visit? I’ve been doing CBC, CMP, urinalysis, Vit D, Mag, phosp, TSH; A1C ( q 3 months on diabetics); lipid pannel; the chief doctor told us we’re doing too much!! What’s your thought on that?

    Reply
  3. Jailaid

    Thanks for this very brief but also a very precise explanation, Jeff! I’ve been to fasting lab facilities where they let the inmates to be tested have their breakfast meal for as early as 5 am so that they will get their blood tested shortly after an hour or two.

    Reply

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