In primary hyperparathyroidism, parathyroid hormone (PTH) levels are either elevated or "inappropriately normal" in the presence of elevated calcium. Typically, PTH levels vary greatly over time in the affected patient and (as with Ca and Ca++ levels) must be retested several times to see the pattern. The currently accepted test for PTH is "intact PTH", which detects only relatively intact and biologically active PTH molecules. Older tests often detected other, inactive fragments. Even intact PTH may be inaccurate in patients with kidney dysfunction. Intact pth blood tests may be falsely low if biotin has been ingested in the previous few days prior to the blood test.