<s>[INST] Hello doctor,My sister’s blood report shows CPK was 290, which is on the higher side. So, the doctor advised checking B12 and it was found to be 185.3. What further investigation is required? She is 65 years old. [/INST] Hello. CPK (creatine phosphokinase) is elevated when muscle injury occurs like in the case of myositis, muscle trauma, heart attack, etc. It had no relation with B12 level. Your CPK is only mildly elevated. Your B12 is definitely high for which following investigations can be done: All these investigations will rule out liver disease, kidney disease, and blood abnormality, if present. These all can affect B12 level. According to reports, further comment can be given. For more information consult a hematologist online --> </s>