High PTH 

A raised PTH level generally indicates hyperparathyroidism, which may be: 

• Primary (parathyroid gland overactivity), often presenting with high calcium. 

• Secondary (compensatory increase), commonly due to vitamin D deficiency or chronic kidney disease, where calcium levels are low or normal. Within the bone profile context, elevated PTH helps explain abnormalities in calcium and phosphate metabolism.  

Low PTH 

Low PTH levels suggest hypoparathyroidism, typically associated with low calcium and possible causes such as autoimmune disease, postsurgical parathyroid damage, or magnesium disturbances.
In bone profile framework, low PTH contributes to impaired calcium regulation and can explain persistent hypocalcaemia.