A 68-year-old Indian-American woman is brought to your office by her son because she has been complaining of diffuse soreness that has been going on for at least one year. She describes it as a severe deep ache involving the neck, shoulders, back, hips and thighs. Her medical history includes a Billroth type II gastrectomy three years ago. She has not seen a doctor since that surgery. Her husband died a year ago. Since then, she became increasingly despondent and confined herself to the basement of her son’s house, without any real sunlight exposure. Most of the time she has been bed-bound. She had been a strict vegetarian, excluding all dairy products from her diet. She eats mostly broth because of difficulty chewing and swallowing. Physical examination findings are as follows: She has a dark skin complexion; pale conjunctiva, and dry mucous membranes. The lungs are clear to auscultation. The cardiac examination is notable for an S4 gallop. There is wasting of extremities; pain with palpation of all extremities and ⅗ muscle strength in all extremities. You suspect osteomalacia in this patient. Which of the following laboratory findings are characteristic of osteomalacia?
