title: Serum calcium (S-Ca), the forgotten test: preliminary results of an appropriateness strategy to detect primary hyperparathyroidism (pHPT).
abstract: BACKGROUND
  With the introduction of automated calcium measurements with multichannel continuous-flow analyzers in the 1970s, primary hyperparathyroidism (pHPT), the silent disease, began to be detected. Years later, with the first appearance of random access analyzers, laboratory tests were requested if the patient had clinical symptoms and pHPT was again overlooked. In this current scenario, serum calcium (s-Ca) is at risk of becoming a forgotten test. In consensus with endocrinologists and general practitioners (GPs), we implemented a strategy to detect asymptomatic pHPT patients.
  
  
  METHODS
  During a 9 month period, the Laboratory Information System automatically added s-Ca to every sample of blood from primary care patients older than 45 years, without a s-Ca request in the previous three years. If hypercalcemia was detected (albumin-corrected s-Ca > 2.6 mmol/L), phosphate, 25-hydroxy vitamin D and parathyroid hormone (PTH) were automatically processed in the same sample. We reviewed the medical record of every patient with hypercalcemia.
  
  
  RESULTS
  S-Ca was automatically added to 14,461 samples, with 79 hypercalcemia results. 14 hypercalcemia results with PTH levels in the reference range were clinically justified by causes other than pHPT. Of the remaining 65 patients, 41 were referred for evaluation by endocrinology. 34 resulted in a diagnosis of pHPT and 7 are currently in study. 24 patients were not followed by GPs to find out the primary cause of hypercalcemia. After a phone call from the laboratory, they are also currently being studied for hypercalcemia. Each case represented a cost of 110.4 US dollars.
  
  
  CONCLUSIONS
  Our proposed opportunistic screening to discover pHPT seems cost-effective.
authors.affiliation: Clinical Laboratory Department, Hospital Universitario de San Juan, San Juan de Alicante, Spain. salinas_mar@gva.es
authors.forename: Maria
authors.initials: M
authors.lastname: Salinas
authors.forename: Maite
authors.initials: M
authors.lastname: López-Garrigós
authors.forename: Francisco
authors.initials: F
authors.lastname: Pomares
authors.forename: Javier
authors.initials: J
authors.lastname: Lugo
authors.forename: Alberto
authors.initials: A
authors.lastname: Asencio
authors.forename: Luis
authors.initials: L
authors.lastname: López-Penabad
authors.forename: Jose Ramón
authors.initials: JR
authors.lastname: Dominguez
authors.forename: Carlos
authors.initials: C
authors.lastname: Leiva-Salinas
mesh_terms: D002118:Calcium / Q000097:blood*; D003710:Demography; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D058005:General Practitioners; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D049950:Hyperparathyroidism, Primary / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged
chemical_list: D002118:Calcium
keywords: 25-(OH)D; 25-OH vitamin D; Appropriateness; GPs; LIS; MR; PCCs; PTH; Primary hyperparathyroidism; S-Ca; Serum calcium; general practitioners; laboratory information system; medical record; pHPT; parathyroid hormone; primary care centers; primary hyperparathyroidism; serum calcium