This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: vitamins, Subject name: Biochemistry
[{'content': 'Diagnosis of folic acid deficiency is done by all except \nSelect and explain. \nA. FIGLU estimation, B. Peripheral blood smears, C. AICAR estimation, D. transketolase activity', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Blood Level: Normal folic acid level in serum is about 20 nanograms/ml and about 200 microgram/ml of packed cells. The level is measured by radioimmunoassay. Histidine load test or FIGLU excretion test: Histidine is normally metabolised to formimino glutamic acid (FIGLU) from which formimino group is removed by THFA. Therefore in folate deficiency, FIGLU is excreted in the urine. AICAR excretion: In the purine nucleotide synthesis, the last step is the addition of C2 with the help of N10-formyl THFA, the precursor, aminoimidazole carboxamide ribosyl-5-phosphate (AICAR) accumulates and is excreted in the urine. Peripheral blood picture. Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 475, 297', 'role': 'assistant'}]