Dear Doctor, I apologize for the long mail. This question is regarding Hyperphosphatemia and suspected kidney troubles in my mother, 52 years old. She has a medical background of hypothyroidism. Two months ago, she was on Levothyroxine 25 mcg because of TSH reading of 11 uIU/mL. After two weeks of this medication, her TSH dropped to 0.19 uIU/mL, moving to hyperthyroidism, so she was advised to discontinue dosage. A lab test on November 4 revealed an extremely elevated TSH of 26.48 uIU/mL, and Creatinine reading of 1.03 mg/dL. BUN was 7.8 mg/dL, Urea was 16.9 mg/dL, but calculated eGFR was low, at 63 mL/min/1.73 sq.m. Following medical advice, we restarted thyroid medication at a lower dose, 12.5 mcg of Levothyroxine. She was also advised to drink sufficient water. After one week, on November 13, we did a detailed Renal Profile and thyroid profile. TSH was now lowered to 20, and the Renal readings were as follows: Cystatin C: 0.89 mg/L || CALCIUM 9.62 mg/dl (8.8-10.6) || URIC ACID 3.75 mg/dl (3.1-7.8) || BLOOD UREA NITROGEN (BUN) 7.45 mg/dl (7-25) || CREATININE – SERUM 0.64 mg/dl (0.5-0.8) || BUN / SR.CREATININE RATIO 11.64 (Ratio 9:1-23:1) || SODIUM 142.2 mmol/l (132-146) || POTASSIUM 4.75 mmol/l (3.5-5.5) || CHLORIDE 100.9 mmol/l (99-109) || eGFR: 103 mL/min/1.73 m^2. || Urinary Albumin to Creatinine ratio: 4.7 ug/mg of Creatinine. But, the phosphorous reading was at 9.9 mg/dL. Since this could indicate kidney problems, this has worried us, and we would highly appreciate your expert opinion. She does not have any noticeable symptoms and urination is healthy when she takes enough water. Her T3, T4 (Free as well as total) readings were always normal. Hypothyroidism is induced due to Autoimmune thyroiditis, as per tests. Thank you very much for your time.

I am unable to evaluate laboratory testing in this situation. The remarkable degree of laboratory variation that you describe is very concerning for the reliability of the laboratory. I am unable to provide a specific diagnosis based on the information that you present. My first question would be towards the reliability of this particular laboratory. I would also need to know much more about recent medications taken and recent dietary changes. I recommend that you review this with a local physician who is familiar with your mother’s medical history and can perform a complete physical examination.