Q. Do increased levels of RBC and vitamin B12 indicate early onset polycythemia vera?

Answered by
Dr. Goswami Parth Rajendragiri
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on May 04, 2017 and last reviewed on: Sep 07, 2021

Hi doctor,

My RBC levels have been slightly elevated for the past six months. It was 5.17 a year back, and a couple of months back it was 5.39. I noticed that from the last two years, the RBC count has been borderline high. Last week my vitamin B12 was tested due to a nerve issue in my face, which came back elevated. My MCH and MCV are always low or borderline low. My WBC, hemoglobin, and hematocrit levels, are all in the normal range. I am concerned that the RBC and vitamin B12 levels might indicate early onset polycythemia vera. I have not taken any supplements of vitamin B12 nor am I taking any supplements with vitamin B12 in it. Also, I got a full thyroidectomy due to stage 1 papillary carcinoma, a year back. Do you think I might be concerned for nothing? Thank you for your time.



Welcome to

I appreciate your knowledge and awareness towards your health, and I have seen your reports (attachment removed to protect patient identity).

  • Your vitamin B12 level is certainly high, enough that warrants further investigation. Following are the common causes for high vitamin B12 level.
  1. Excess intake of vitamin B12 supplement.
  2. Any liver disorder.
  3. A myeloproliferative disease like polycythemia or CML (chronic myeloid leukemia).
  4. Any cancer and kidney disease.
  • Now as your RBC (red blood cells) are elevated, first of all, polycythemia vera comes in mind, but normal hemoglobin and hematocrit levels are against the diagnosis of it. Regular screening should be done up to one year at least, if hematocrit and hemoglobin are increasing, then JAK 2 mutation study can be done for its confirmation.
  • In myeloproliferative disorder, WBC (white blood cells) count is usually high which is normal. If in screening, the WBC count is increased, then it can be confirmed by BCR-ABL t(9;22) study by molecular testing.
  • Evaluate liver functions by serum SGPT (serum glutamic pyruvic transaminase), SGOT (serum glutamic oxaloacetic transaminase), serum albumin and ultrasound. Kidney function test also should be evaluated with serum creatinine and serum urea like investigations.
  • Avoid alcohol. Consult a nearby physician for examination and regular screening. If no cause is found in subsequent follow-up, and vitamin B12 level comes to normal, then it might be elevated because of papillary carcinoma history.

For further queries consult a hematologist online -->

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