A doctor will determine if a patient has hypothyroidism through a detailed exam including history, symptoms, and blood work. The classic symptoms of low calcium will prompt further tests of parathyroid hormone levels, calcium, phosphorus, magnesium, and creatinine. Vitamin D and urine can also indicate the problem. Medical professionals can test for low calcium by inflating a blood pressure cuff past the systolic blood pressure level. In patients with low calcium, this will often cause the hand to spasm into a hook-like arch called Trousseau's sign.

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