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Author: Mikael Häggström [note 1]
As further detailed at Learning pathology, memorization-worthy information includes pitfalls, which mainly relate to situations where there is a significant risk of error even after using resources such as looking it up. An efficient way of learning about a potential pitfall is to fall into it, and therefore, this chapter is structured as case descriptions, some of which are significant pitfalls, and some of which are not, so that you can safely learn about them without harming real world patients. Case descriptions also aim to present you with pertinent look-up information, so you can get a better idea of what you don't need to directly memorize. Further information: Learning pathology

Molecular pathology

You are on call during the night, with a senior pathology trainee and an attending to call when needed. At 2:00 AM you receive a call from the chemistry lab about a critically low blood glucose value of 40 mg/dL.

  • Quick look-up information (you don't need to memorize this): The lower limit of the reference range for blood glucose is generally 65[1] to 70[2] mg/dL.

You decide to first wake up your senior resident, who tells you that the blood glucose may be falsely low if there was a prolonged time from blood collection to centrifugation, especially if more than 4 hours has passed, because the red blood cells will consume glucose from the plasma by glycolysis. Therefore, you want to check the collection times with the lab, so you call a technician there, who informs you that the blood was collected at an outpatient location and there was more than 6 hours from collection time to the time they received it in the lab. You access the medical records through VPN on your computer, and there was no mention of hypoglycemic symptoms from the patient visit, and that outpatient clinic is now closed. You subsequently discuss this information with your senior resident again, and come to the agreement to tell the lab to hold the result for now due to a high probability of being falsely low, and to wait until the next workday to reach out to the outpatient clinic to ask whether they centrifuge their blood samples before sending them to the lab. You don't need to report everything to the attending physician right away, so you decide to go back to sleep.

Did you make a significant error in this case, and if so, what?

Answer (preferably don't read until you have made up your mind): The handling of this situation is generally sufficient.


  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

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  1. Normal Reference Range Table Template:Webarchive from The University of Texas Southwestern Medical Center at Dallas. Used in Interactive Case Study Companion to Pathologic basis of disease.
  2. Last page of Deepak A. Rao; Le, Tao; Bhushan, Vikas (2007). First Aid for the USMLE Step 1 2008 (First Aid for the Usmle Step 1) . McGraw-Hill Medical. ISBN 978-0-07-149868-5. 

Image sources