title: Serum potassium, sodium and calcium levels in healthy individuals - literature review and data analysis.
abstract: OBJECTIVE
  The human body is known to be composed of 24 elements, among which potassium, sodium and calcium are considered to be essential. These necessary components play a significant physiological role which includes regulation of the electrical and mechanical action of the heart. Abnormal concentration of the above-mentioned ions, i.e. water-electrolyte imbalance, may result in cardiac arrhythmias, muscle contraction disorders, disturbances of neuronal activity and influences the drugs activity.
  
  
  METHODS
  The study aimed at gathering and analyzing results of publicly available research which reported serum concentration of these ions. This information, together with an additional collection of data (gender, age, height, weight, measurement method), is presented in table form attached as supplementary material.
  
  
  RESULTS
  The serum ions concentrations means weighted by the study-specific sample sizes indicated statistically significant differences between males and females for all ions - K+ 4.21 and 4.09, Na+ 140.1 and 138.17, Ca2+ 2.42 and 2.31 respectively).
  
  
  CONCLUSIONS
  Obtained results correspond with the current laboratory reference values. As potassium, sodium and calcium follow the circadian rhythm, publications reporting serum concentration values were also collected and presented. Further studies are planned to describe such phenomenon in a form of the statistical model.
authors.forename: Kamila
authors.initials: K
authors.lastname: Fijorek
authors.forename: Mirosława
authors.initials: M
authors.lastname: Püsküllüoğlu
authors.forename: Dorota
authors.initials: D
authors.lastname: Tomaszewska
authors.forename: Roman
authors.initials: R
authors.lastname: Tomaszewski
authors.forename: Anna
authors.initials: A
authors.lastname: Glinka
authors.affiliation: Unit of Pharmacoepidemiology and Pharmacoeconomics, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, Poland. Simcyp Limited, Blades Enterprise Centre John Street, Sheffield S2 4SU, UK. spolak@cm-uj.krakow.pl.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Polak
mesh_terms: D002118:Calcium / Q000097:blood*; D002940:Circadian Rhythm; D005260:Female; D006304:Health Status; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D011188:Potassium / Q000097:blood*; D012016:Reference Values; D012737:Sex Factors; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium; D011188:Potassium; D002118:Calcium
keywords: calcium; healthy volunteers; potassium; serum; sodium