Medical Lectures

QUIZ: Abnormal CBC – When to Phone a Hematology Friend

Do you know everything there’s to know about abnormal CBC? Take this quiz and test your knowledge.
March 31, 2022
Jeanne Palmer, MD

Jeanne Palmer, MD reviews case by case workups and what actions are appropriate defined by the CBC results. Review Abnormal CBC pearls and what you can do before you refer your patient to hematology by watching the video below.


Which patient should you send to the ER on Friday evening?

a. WBC of 75,000 with many cell types on diff

b. WBC of 75,000 with 90% blasts

c. Both

d. Neither

Answer (B)

What is an uncommon but possible symptom of iron deficiency anemia?

a. restless leg syndrome

b. constipation

c. vomiting

d. fevers

Answer (A)


So case one, you have a 67-year-old female who presents with CBC that has a hemoglobin of 8.2, hematocrit 25 and elevated MCV at 105 platelets at 90 and white blood cells of 5.3 with a normal differential. 

So, as most I'm sure everyone does in normal anemia work up, including iron studies, B12, folate, SPEP, TSH, reticulocyte count. And everything's normal, except for that there's a low B12.

So, B12 replacement, just a couple of things. It's more common if you have a patient who's vegan, so who doesn't eat dairy or meat products. These are people who you really want to make sure you're looking for a B12 deficiency because you get B12 from sort of dairy and beef and stuff like that. You always want to think about celiac disease or pernicious anemia. 

And then even in the case where somebody has the parietal cell deficiency, where they can't absorb B12 appropriately, usually if you replace them with B12 at 1,000 micrograms a day, which is this 1 milligram standard dose that you can get over the counter, that should actually be able to overcome even people who have pernicious anemia. So, always think about that. Now, some people feel better with the B12 injection and there's really no problem with giving a B12 injection, but I always try them on oral first. 


So, let's take two on that case. If you have the same woman, same findings, but her platelets are 59, and you've replaced her B12 and, everything is normal from her anemia workup, if you see an elevated MCV along with low white blood cell count or low hemoglobin, low platelets, you always want to think of myelodysplastic syndrome. 

This is a situation where you want to refer somebody to a hematologist cause if they do have myelodysplastic syndrome, you want to know about it cause it can be a fairly significant and problematic disease. 

So again, an elevated MCV in the absence of finding like a B12 or folate deficiency, you always want to think about myelodysplastic syndrome and refer to hematology. Alright, so a different 67 year old woman, I suppose, comes in and has the following CBC: a hemoglobin of 8.2, hematocrit 25. MCV, however, is 76. White blood cell count, which at 76, is low. White blood cell count of 5.3 and platelets of 723. She is fatigued and also has restless leg syndrome. 


So, you do the normal anemia workup and all is normal except iron studies. So in her case, her iron was 67. Her TIBC was 428, which is elevated, and her ferritin is 15. So a couple things, you'll say, "Well, geez, the iron's actually normal.” In patients taking iron, like let's say even a prenatal vitamin has enough iron to do this, their actual iron in their blood, if they're actively taking iron pills, will be high. So you can't always trust just to iron in the blood. 

Her TIBC is elevated, and that's one of the proteins that's produced by the liver that helps bind iron. If that's elevated, that is a sign of iron deficiency in her ferritin is 15. So, when you're doing iron studies, I often see that ferritin is one thing that's overlooked. Always remember to do the ferritin because sometimes that will be the most telling thing, especially if somebody is taking any type of vitamin or something else. 

Now, if they have inflammatory disease, like inflammatory bowel disease or something, their ferritin could easily be elevated just from that. And if their ferritin is greater than 100 or less than 100 in that situation, they still may be iron deficient, especially if they have a low iron to TIBC ratio or are just low iron in general….

Watch the video to learn more.

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