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Venous blood samples were withdrawn pre-operatively and at 12, 24, 48, 72 and 168 h post-operatively from 11 patients (6 males and 5 females) who were admitted for elective knee arthroplasty.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.
Scottish Trace Element and Micronutrient Reference Laboratory, Royal Infirmary, Glasgow G4 0SF, UK. eleanor.oakes@nhs.net
Eleanor J C
EJ
Oakes
Thomas D B
TD
Lyon
Andrew
A
Duncan
Andrew
A
Gray
Dinesh
D
Talwar
Denis St J
DS
O'Reilly
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