Albumin-adjusted calcium is not suitable for diagnosis of hyper- and hypocalcemia in the critically ill.
OBJECTIVE
To evaluate whether calcium adjusted for albumin can be used to monitor calcium homeostasis in critically ill patients.


METHODS
Prospective single-single center observational study.


METHODS
Clinical laboratory and critical care unit of a regional teaching hospital.


METHODS
Fifty-three paired samples were from 36 patients requiring intensive care treatment.


METHODS
None.


RESULTS
Total calcium, albumin-adjusted calcium, and ionized calcium were measured in critically ill patients during an 8-wk period. Calcium was adjusted for albumin using the formula that is most frequently used in The Netherlands. Using ionized calcium as the gold standard, albumin-adjusted calcium overestimated hypercalcemia and totally missed hypocalcemia. The same seemed to be true for other formulas used for albumin or protein adjustment of calcium concentrations.


CONCLUSIONS
Albumin-adjusted calcium cannot be used in an intensive care setting to monitor reliably the calcium levels in critically ill patients and should be replaced by measurement of ionized calcium.
Slomp
Jennichjen
J
Department of Clinical Chemistry, Stichting Klinisch Chemisch Laboratorium, Leeuwarden, The Netherlands.
van der Voort
Peter H J
PH
Gerritsen
Rik Th
RT
Berk
Jan A M
JA
Bakker
Andries J
AJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015982:Bias; D001784:Blood Gas Analysis; D002118:Calcium / Q000097:blood*; D016638:Critical Illness; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006706:Homeostasis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006934:Hypercalcemia / Q000097:blood*; D006996:Hypocalcemia / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods* / Q000592:standards; D009426:Netherlands; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis*
D012709:Serum Albumin; D002118:Calcium