6th February 2024

A 34-year-old female with Hashimoto’s thyroiditis was found to have an anaemia on routine blood tests.

A 34-year-old female with Hashimoto’s thyroiditis was found to have an anaemia on routine blood tests. She states she has felt increasingly breathless and tired over the past three months. Her thyroid functions were normal, but blood MCV measured 120 fL(normal 80-100 fL). Following further blood tests showing a vitamin deficiency, anti-gastric parietal cell antibodies were detected. 

Which of the following vitamin deficiency is present?