February 2, 2009Kaela Leonard
| Kaela Leonard - “Effect of In Vitro Hemolysis on 25 Common Biochemical Tests”
Dogan Yucel and Klara Dalva
Prepared by: Kaela Leonard
| | | | Summary:
Article examined the effect of hemolysis on 25 different common biochemical tests. They lyzed the cells in two different steps to obtain three levels of hemolysis- nonhemolyzed, moderately hemolyzed and severely hemolyzed. It was found that the hemoglobin concentration was significantly different between moderately and nonhemolyzed and then severely and moderately.
After hemolysis, the samples were subjected to 25 biochemical tests. The results were analyzed to determine if moderate or severe hemolysis had a significant impact on the analyte concentration. It was found that only lactate dehydrogenase, potassium, acid phosphatase and prostatic acid phosphatase were significantly increased by hemolysis. This increase was even more significant for the severely hemolyzed cells.
Outline:
1. Abstract
a. Examines effect of hemolysis on biochemical tests
b. Mechanically hemolyzed 10ml of sample
c. 3 levels of hemolyzed cells
d. Greatest effect on tests for:
i. Lactate dehydrogenase
ii. Acid phosphotase
iii. Potassium
2. Introduction
a. Hemolysis common when blood contacts a foreign surface
b. Can result from improper handling of specimen or procedures such as centrifugation
c. Important to know what the effect of a partially hemolyzed sample would do to the results of a biochemical test
d. Visible when hemoglobin concentration is greater than 3.1mol/L
e. Hemolysis has a effect on constituents that are present in greater concentration in erythrocytes than in plasma
f. May also influence the colorimetric determination of constituents
i. Colorimetric- determination of concentration of constituents by visually comparing the color of the solution with the color of a standard solution
3. Materials and Methods
a. 60- 15mL samples from patients in various hospital units
b. Centrifuged 5mL samples for 10 minutes at 1500- obtaining 2mL samples of nonhemolyzed serum
c. The remaining 10mL was hemolyzed by mechanical stirring with a metallic bar
i. Obtain moderately and severely hemolyzed cells as a result
d. Method chosen because it was close to mechanical lysis that occurs during problematic sample acquisition and preparation
e. Measured Hb in each sample and classified it as:
i. Nonhemolyzed (Group I)
ii. Moderately hemolyzed (Group II)
iii. Severely hemolyzed (Group III)
f. Used a variety of analytical equipment to test for different enzymes (too many to list- refer to last paragraph of the first page of the article)
4. Results
a. It was found that the difference in Hb concentrations between I and II and II and III were statistically different
b. Differences between I and II and then I and III were determined for each test
i. Only lactate dehydrogenase, potassium, acid phosphatase and prostatic acid phosphatase were sig. increased by hemolysis in group II
1. Increase even more significant for group III
ii. Cholesterol concentration also sig. increased in group III
c. Slightly decreased values for glucose, uric acid, alkaline phosphatase, lipase, total and direct bilirubin
d. Slightly increased values for aspartate aminotransferase, alanin aminotransferase, lipoprotein cholesterol, triglycerides and inorganic phosphate- however not sig.
e. Plotted change for each test vs. change in Hb concentration
5. Discussion
a. Results show that dehydrogenase, potassium, acid phosphatase and potassium sig. affected by hemolysis- agrees with previous results
b. Slight decrease in glucose and uric acid, effect explained by reactions involving hydrogen peroxide because of premature decomp of hydrogen peroxide by Hb
c. Increase in cholesterol due to Hb??—How did they come to this conclusion?
d. Results for other tests not impacted by hemolysis even in the severe case
i. Hb may mask titration end for these tests- positive errors can occur
ii. Results agree well with previously reported
e. In contrast to previous studies
i. Prostatic acid phosphatase affected by hemolysis
ii. Negligible increase in aspartate aminotransferase
f. Effects of hemolysis method-dependent
g. Results for lactate dehydrogenase, potassium, acid phosphatase and prostatic acid phosphatase and potassium analyses have to be rejected if hemolysis occurs
h. However, correlation could be made if calculation of free Hb is done
Recommendation:
Accept without revisions, but would look forward to seeing a more in-depth discussion of the research. They talk about plots that were created but never show any of these.
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