Diagnosis of arginine vasopressin deficiency in a patient with 10 years of polyuria and polydipsia following an Epstein-Barr virus infection.

Polyuria-polydipsia syndrome is composed of arginine vasopressin deficiency, arginine vasopressin resistance and primary polydipsia and are characterised by severe polyuria with hypotonic urine. The water deprivation test is commonly used to indirectly assess the vasopressin response to water deprivation. We report a woman in her 20s who demonstrated severe polyuria (11-12 L/day) on submitting a 24-hour urine sample for analysis.

Falsely low glycosylated haemoglobin levels probably secondary to hypersplenism in a patient with diabetes mellitus.

A man in his 70s presented with a history of low glycated haemoglobin (HbA1c) values despite a diagnosis of type 2 diabetes. His blood glucose readings ranged between 8 and 15 mmol/L, but his HbA1c values were below 27 mmol/mol. Initial investigations demonstrated evidence of reduced red blood cell lifespan as a cause of misleadingly low HbA1c values.