Heparins plasma

The analysis of human plasma for acetaminophen, the active ingredient in some pain relievers, involves a unique extraction procedure. Small-volume samples (approximately 200 fiL) of heparinized plasma, which is plasma that is treated with heparin, a natural anticoagulant found in biological tissue, are first placed in centrifuge tubes and treated with 1 N HC1 to adjust the pH. Ethyl acetate is then added to extract the acetaminophen from the samples. The tubes are vortexed, and after allowed to separate, the ethyl acetate layer containing the analyte is decanted. The resulting solutions are evaporated to dryness and then reconstituted with an 18% methanol solution, which is the final sample preparation step before HPLC analysis. The procedure is a challenge because the initial sample size is so small. 

Randy Karl of MDS Pharma Services in Lincoln, Nebraska, examines a centrifuge tube containing a heparinized plasma sample prior to performing an extraction procedure using ethyl acetate. 

Another major site of peptide metabolism is the blood and especially blood serum and plasma. From an extensive compilation of peptide tm values (over 100 peptides, plus derivatized and cyclized analogues, D-amino acid stereoisomers, peptide bond isosteres, etc.), it appears that the differences between serum, heparinized plasma, and whole blood are fairly limited [161]. Interspecies differences are larger, particularly between humans and rats, with most human/rat t1/2 ratios ranging from 1 1 to 25 1 ... 

Oxalate does not interfere with glucose assays, but insulin values determined in oxalate-plasma are lower than those obtained with lithium heparin-plasma or serum (L6). Specimens collected in EDTA demonstrate lower carbon dioxide combining power than those observed with serum or heparin or potassium oxalate plasma (Zl). 

Enzymes activities are particularly sensitive to the anticoagulant used in collecting the specimen. Heparin inhibits acid phosphatase (W16) and muramidase (Z5). Amylase activity is inhibited by oxalate or citrate (MIO), and lactic dehydrogenase and acid phosphatase lose activity in oxalate (C2). Alkaline phosphatase is stable in oxalate, oxalate-fluoride, or heparin, but 25 mAf citrate inhibits 50% of the activity, and as little as 50 mlf EDTA is completely inhibitory (B19). Leucine aminopeptidase is inhibited by EDTA, as is creatine phosphokinase (F3). Amylase activity has been reported to be only 83% of that in serum when oxalate or citrate-plasma is used (MIO). Heparin plasma appears to have no inhibitory effect. Despite the fact that clotting factor V is not stable in oxalate or EDTA, these are often used as anticoagulants to obtain plasma for prothrombin determinations (Z2, Z4). 

Gl. Ganesan, D., and Bradford, R. H., Isolation of apolipoprotein-free lipoprotein lipase from human post-heparin plasma. Biochem. Biophys. Res. Commun. 43, 544-549 (1971). 

A variety of body fluids can be used for acylcarnitine analysis. While initially the favored specimen, urine acylcarnitine analysis is the least appropriate when an FAO disorder is under diagnostic consideration. Heparinized plasma or whole blood spotted on filter paper are preferred in this context. 

Early research on lipolytic enzymes in cows milk suggested that at least two major lipases were present a plasma lipase in the skim portion and a membrane lipase associated with the milk fat globule membrane (Tarassuk and Frankel, 1957) while later research indicated that there might be up to six different molecular species with lipase activity (Downey and Andrews, 1969). However, work by Korn (1962) showed that milk contained a lipoprotein lipase (EC 3.1.1.34) (LPL) with properties very similar to those of post-heparin plasma, adipose tissue and heart LPLs, particularly the enhancement of its activity on emulsified triglycerides by blood serum lipoproteins. It is now accepted that LPL is the major, if not the only, lipase in cows milk. Its properties have been reviewed by Olivecrona et al. (2003). 

Table 5-2. Heparin-Plasma 99th Percentile Reference Limits ( ig/L) by Gender and Race for Cardiac Troponin Assays Cleared by the Food and Drug Administration ...

Fresh or frozen heparinized plasma of different species (pool), collected from fasted animals and humans). If frozen plasma is used, the pH value has to be adjusted (see adjustment of pH at chapter ultrafiltration)... 

The rate of triglyceride output from the plasma is mainly controlled by the lipoprotein lipase activity of peripheral tissues. Post-heparin plasma lipolytic activity in vitamin-C-deficient guinea pigs decreases considerably. In addition, in some of the animals the response of the plasma lipolytic activity to intravenously administered heparin is also prolonged (45). Similar results have been reported in vitamin-C-deficient baboons (46). 

Sample material Serum, heparin plasma, EDTA plasma or fluoride plasma. 

Sample material Acidified serum, acidified EDTA plasma or acidified heparin plasma. 

Sample material Serum, lithium heparinate plasma or sodium heparinate plasma. 

EDTA, potassium oxalate, sodium citrate and sodium fluoride are unsuitable for plasma separation. Lithium heparin plasma or sodium heparin plasma will show approx. 20 U/1 higher values than serum. 

Sample material Serum or heparin plasma. Interferences ... 

Range of measurement 5.0-40.0 mmol/1. Reference interval 22-30 mmol/1. Sample Serum or heparin plasma. Interferences ... 

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