Hemolysis and Lipemia

Some analyzers have programs that assess the degrees of hemolysis and lipemia in the samples, but these are designed for use with human samples (Vermeer, Thomassen, and de Jonge 2005) and some dyes (e.g.. Patent Blue V. can interfere with these serum indices but not the analytical methods Darby and Broomhead 2008). Some xenobiotics may interfere due to their fluorescent properties. 

These are examples of endogenous causes of interference in some plasma measurements. The presence of hemolysis can affect colorimetric methods using absorbance 

Lipemia may interfere with some measurements through turbidity (Hortin and Goolsby 1997) or by alterations to the plasma volume (McGowan, Artiss, and Zak 

1984) (e.g., plasma displacement effects causing pseudohyponatremia Weisberg 

The turbidity due to lipemia may be reduced by ultracentrifugation or precipitation techniques, but these procedures may alter apparent analyte concentrations (Thompson and Kunze 1984). Synthetic lipid emulsions are often used to test for effects caused by lipemia, but these emulsions do not always mimic the physicochemical effects of hyperlipemia caused by perturbations of lipid metabolism (Bornhorst, Roberts, and Roberts 2004). 

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Serum or plasma is used for the measurement of TSH and the thyroid hormones, with serum free of hemolysis and lipemia preferred. Specimens are stable for 5 days at 2 °C to 8 °C and for at least 1 month when stored frozen. For newborn screening, whole blood is collected by heel puncture 48 to 72 hours after birth. 

Jacobs, R. M., J. H. Lumsden, and E. Grift. 1992. Effects of bUirnbinemia, hemolysis and lipemia on clinical chemistry analytes in bovine, canine, equine and feline sera. Canadian Veterinary Journal 33 605-607. 

Westgard, JC, Effects of Hemolysis and Lipemia on ACA Creatinine Method, 0.200 iL, Sample Size, Du Pont Company, Wilmington, DE (Cctober 1972). 

Mild to moderate hemolysis in antiserum resulting from sub-optimal bleeding techniques probably does not interfere with most immunohistochemical staining procedures, but excessive hemolysis should be avoided. If excessive hemolysis or lipemia is encountered, isolation of the immunoglobulin fraction from the antiserum may be necessary. Such isolates will usually appear colorless and clear. Discard all immunochemicals, including antisera and normal non-immune sera contaminated with bacterial growth. Their use in... 

D. Specimen List type of specimens that can be used and recommended volume and minimum volume. Indicate conditions that render the specimen unacceptable, such as hemolysis or lipemia. List patient preparation procedures. Provide instruction for specimen handling before testing. 

Plasma creatinine is an imperfect marker of GFR and therefore it is not altogether surprising that formulas based predommantly upon it are imperfect. Their use cannot circumvent the very significant spectral interferences affecting plasma creatinine measurement (i.e., hemolysis, icterus, and lipemia) and the formulas are unsuitable for use in patients with acute renal failure, in whom plasma creatinine concentrations are changing rapidly. Additionally, the formulas are critically susceptible to variations in creatinine assay calibration and specificity. Notwithstanding the MDRD formula is thought to improve the estimation of GFR compared with plasma creatinine alone. 

Disadvantages include the greater interference of hemolysis, icterus, and lipemia at 340 nm. Approximately 70% of laboratories participating in the College of American Pathologists Comprehensive Chemistry Survey in 2004 used a direct UV procedure, with most of the others using a reduced photometric method. 

Finally, analytical accuracy, precision, and freedom from interferences must meet contemporary needs. Precision of modern instruments is largely excellent bias from the true value is a common problem with enzyme assays, and interferences from lipemia, hemolysis, and icterus is still a problem with some instruments and methods. 

El04 Corkey, R., Kahn, S., Kiechle, F, Connelly, L, Powers, D., Walch, D. and Shirey, T. (1983). Kodak Ektachem clinical chemistry slides (NBIL) minimize interference from lipemia and hemolysis. Clin. Chem. 29, 1222, Abstr. 426. 

Level detection and evaluation of specimen adequacy (specimen integrity) An area in which sensors are used to evaluate the volume of specimen in each specimen container and to look for the presence of hemolysis, lipemia, or icterus. 

Interfering substances, especially in patient populations, that require some evaluation may include prescription and over-the-counter medication, herbal medications, dietary substances, and even the presence of antidrug antibodies and associated immune complexes. During sample analysis, new matrix conditions may develop that would require further investigation and could include hemolysis, lipemia, rheumatoid factor, and so on. 

Refractometry Refractometry is a quick and reasonably accurate alternative to chemical analysis for serum total protein when a rapid estimate is required. The refractive index of water at 20°C is 1.330 if solute is added to the water, the refractive index of a dilute solution increases linearly and proportionally to the solute concentration at higher concentrations of dissolved solids (50-200gl ), the increase is nearly linear. Temperature affects appreciably the refractive index of a solution, so refracto-meters for clinical use compensate for temperature effects. Serum contains dissolved solids in concentrations of 80-100 gl, most of which are proteins. In the refractometry of serum, it is assumed that the concentration of inorganic electrolytes and nonprotein organic compounds does not vary appreciably from serum to serum and that the differences in the refractive index reflect primarily the differences in protein concentrations. The assumption has been shown to be reliable for clear, nonpigmented samples, but hemolysis, lipemia, icterus, and azotemia produce erroneously high results. The method cannot be used for urine protein measurement because of excess solutes in relation to the protein. 

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