Primary hyperparathyroidism: Current situation in the clinical and biochemical presentation Primary hyperparathyroidism (pHPT) is the third most common endocrine disease and the most common cause of outpatient hypercalcemia. Historically, most patients presented with overt symptoms and signs of pHPT. With the advent and widespread use of automated blood analyzers, currently the majority of patients are diagnosed through routine biochemical laboratory testing done for other aims. The majority of patients are minimally symptomatic or asymptomatic. The clinical presentation of pHPT varies from asymptomatic disease to classic symptomatic disease in which renal and/or skeletal complications are observed. The term "mild pHPT" has been interpreted in many different ways over the past 30 years. Mild pHPT was clearly defined as a disease in asymptomatic patients who do not meet surgical criteria set out by the updated International Guidelines. Normocalcemic pHPT was first defined formally at the time of the ''Third International Workshop on the Management of Asymptomatic pHPT'' in 2008. Normocalcemic pHPT, a variant of the traditional hypercalcemic presentation of pHPT, is characterized by consistently elevated PTH concentrations with normal total and ionized serum calcium (Ca) concentration in the absence of secondary causes for elevated PTH concentrations. Primary hyperparathyroidism may present as classic pHPT (in which both Ca and PTH are high), nonclassic (normohormonal or nonsuprese) pHPT (in which Ca is high and PTH is normal), normocalcemic pHPT (in which Ca is normal and PTH is high) biochemically. The only curative therapy for pHPT is parathyroidectomy. Parathyroidectomy is clearly indicated in all symptomatic patients. ''Fourth International Workshop on the Management of Asymptomatic pHPT'' had been performed in 2013. Surgical indications for pHPT are determined according to the age, Ca level, skeletal and renal findings. In some patients with asymptomatic disease, surgery is not mandatory. On the other hand, even in these patients who don't meet any criteria for parathyroidectomy, surgery is always an option because it is the only exact treatment for pHPT. The optimal treatment strategy for patients with normocalcemic pHPT has not yet been proved. Experts advise that patients be referred for parathyroidectomy if they have or progress complications of pHPT such as osteoporosis, fragility fractures or kidney stones, even if normocalcemia continues. Patients without complications at the time of diagnosis could be monitored for disease progression.