Acute inflammatory response does not affect erythrocyte concentrations of copper, zinc and selenium.
OBJECTIVE
Measuring the nutritional status of trace elements in plasma is invalidated in the presence of a systemic inflammatory response. We examined the potential of erythrocytes to assess copper, zinc and selenium status in such situations.


METHODS
Venous blood samples were withdrawn pre-operatively and at 12, 24, 48, 72 and 168 h post-operatively from 11 patients (6 males and 5 females) who were admitted for elective knee arthroplasty. C-reactive protein, albumin, copper, zinc, selenium and iron were measured in plasma and erythrocytes.


RESULTS
Plasma zinc and selenium concentrations fell significantly: 95% confidence intervals (CI)=-32% to -44% and -22% to -36%, respectively. Copper concentrations fell transiently and then increased significantly: CI=12-43%. No significant changes were seen in trace element concentrations in erythrocytes expressed either as a ratio of haemoglobin or iron concentration. Erythrocyte iron levels correlated significantly with haemoglobin (r=0.93).


CONCLUSIONS
Plasma concentrations of copper, zinc and selenium are unreliable markers of status in patients with an acute inflammatory response. Erythrocyte concentrations of these trace elements may provide a more reliable measure in long-term studies of patients with a chronic systemic inflammatory response. Iron can be used instead of haemoglobin as the denominator when expressing erythrocyte concentrations of trace elements.
Oakes
Eleanor J C
EJ
Scottish Trace Element and Micronutrient Reference Laboratory, Royal Infirmary, Glasgow G4 0SF, UK. eleanor.oakes@nhs.net
Lyon
Thomas D B
TD
Duncan
Andrew
A
Gray
Andrew
A
Talwar
Dinesh
D
O'Reilly
Denis St J
DS
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D002097:C-Reactive Protein / Q000032:analysis; D003300:Copper / Q000032:analysis / Q000097:blood; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000503:physiopathology; D007501:Iron / Q000032:analysis / Q000097:blood; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D012643:Selenium / Q000032:analysis / Q000097:blood; D012709:Serum Albumin / Q000032:analysis; D014131:Trace Elements / Q000032:analysis / Q000097:blood*; D015032:Zinc / Q000032:analysis / Q000097:blood
D012709:Serum Albumin; D014131:Trace Elements; D003300:Copper; D002097:C-Reactive Protein; D007501:Iron; D012643:Selenium; D015032:Zinc