PTH and endocrine system disorder: In addition, clinical signs along with the measurement of TSH (Thyroid stimulating hormone) and PTH (Parathyroid hormone) will help to rule out endocrine disorders (specifically hyperthyroidism, hypothyroidism, panhypopituitarism, and hyperparathyroidism) as the cause of a hyporegenerative, normocytic normochromic anemia.