Lithium-heparin

The antidiuretic effects of vasopressin may be decreased when die agent is taken witii die following drugs lithium, heparin, norepinephrine, or alcohol. Antidiuretic effect may be increased when die drug is used witii carbamazepine, clofibrate, or fludrocortisone... 

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). 

Measure the influence of heparin human serum samples containing normal levels of electrolytes were anticoagulated with 23.8, 35.7, 47.7 and 128 UI/mL of lithium heparin. 

However, the authors identified a laboratory error, in that the blood tube for analysis for lithium contained lithium heparin rather than sodium heparin. When the infant s serum lithium concentration was checked using a proper tube on day 6 it was 0.06 mmol/1, not 2.6 mmol/1, so the fetus may not after all have had lithium toxicity. 

The inadvertent use of lithium heparin as an anticoagulant in the collection tube will lead to a spuriously high serum lithium determination. 

A similar problem occurred in a 20-month-old with recurrent convulsions, who had an apparent serum lithium concentration of 3.2 mmol/1. The absence of lithium in the urine prompted further investigation and the source of the lithium was found to be from the use of a lithium-heparin collection tube (700). 

Contamination of lithium heparin blood culture bottles with Pseudomonas fluorescens led to an outbreak of pseudobacteremia and the unnecessary treatment of a number of children with antibiotics. Lithium had no direct role in this misadventure (703). 

In blood samples from 32 subjects, TSH and free T4 concentrations were no different in collection tubes that contained a lithium heparin anticoagulant compared with dry tubes, but free T3 concentrations were significantly lower (704). 

Namnyak S, Hussain S, Davalle J, Roker K, Strickland M. Contaminated lithium heparin bottles as a source of pseu-dobacteraemia due to Pseudomonas fluorescens. J Hosp Infect 1999 41(l) 23-8. 

A 33-year-old woman was admitted to an intensive care unit after ingesting unknown quantities of a variety of medications, including lithium. She remained asymptomatic, except for drowsiness, despite serum lithium concentrations of 2.7, 3.1, 3.6, and 5.6 mmol/1. The latter concentration was discovered to be spuriously high when it was realized that blood had been collected in a lithium-heparin anticoagulant tube. When the test was repeated using the proper collection tube, the concentration was 2.2 mmol/1 (571). 

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. 

Sodium heparinate, lithium heparinate, sodium fluoride/potassium oxalate, and EDTA do not cause an interference. Citrate should not be used as an anticoagulant because it may cause a large negative bias. 

Sample material Serum, sodium heparin plasma, lithium heparin plasma or disodium-EDTA plasma. 

Polymer gel/silica.activator/lithium heparin.. Green/gray Light gray... 

The choice of container for samples is important, since contamination from rubber, cork, and colored plastics can be a problem. For blood plasma, collection plastic tubes with lithium heparin as an anticoagulant are suitable for most analyses. For blood serum, plain glass containers can be used. For the uitratrace metals (Mn, Cr), special arrangements have to be made to collect blood via plastic cannulae or silanized steel needles, and then the sample is placed into acid-washed containers. Trace metal vacutainers are avahabie commercially. It is good practice to run dilute acid blanks through all the containers and collection systems to ensure that all batches remain as free from contamination as possible. 

Mouse plasma C57BL6 mouse plasma, mixed sex, lithium heparin anticoagulant (Sanford-Burnham Animal Facilities, La Jolla, CA, USA) (r eNote 1). Store aliquots at -20 °C. Store thawed aliquot on ice and flash-freeze the remaining blood sample at end of assay day. 

In t ie case of animal plasma preparation, an anticoagulant is necessary to maintain solubility of blood components, and sodium citrate or lithium heparin would be preferable over any alternatives that contain EDTA. EDTA will chelate magnesium and zinc ions and require much higher concentrations of the two ions in the assay buffer for acceptable hnal ion concentrations, possibly to the point of precipitation. 

FIGURE 9.2 A comparison of two calibration curves in cynomolgus monkey plasma. One curve was prepared in K3 EDTA plasma and the other in lithium heparin plasma. Each calibrator contained 2% of the corresponding matrix prepared from the same stock solution of drug, spiked directly into 100% plasma and then diluted 50 fold in assay buffer. The pH of the diluted calibrators was 7.4 for each matrix. 

Lithium heparinate is the anticoagulant of choice for plasma electrolyte measurements (except, of course, for plasma lithium). Falsely elevated potassium values occur when potassium sequestrenated (EDTA) samples are measured, and the anticoagulant sodium heparinate will give falsely elevated sodium values. Sodium fluoride is a suitable anticoagulant for plasma lactate measurements and is more convenient than iced perchloric acid (Evans 1987). 

Information on the contamination resulting from the use of anticoagulants is very scanty. Lead in heparin does not contribute significantly to the concentration of lead in whole blood, whereas for lead in plasma it does, as the concentration of lead in plasma is very low (Everson and Patterson, 1980 Cavalier and Minoia, 1981). Sodium citrate and lithium heparin were reported to contain too high concentrations of aluminium (d Haese et al., 1985), while potassium EDTA from one source - but not from another - could be used for plasma aluminium analyses (d Haese et al., 1985 Paudyn et al., 1989). Potassium EDTA from a further source was found suitable for the analysis of cobalt in whole blood (Angerer and Heinrich, 1984) however, in an analysis of a large number of trace elements, and several anticoagulants, contamination was most frequently encountered when EDTA was used (Paudyn et al., 1989). 

The type of anticoagulant used during collection of the blood sample may also affect the stability of drugs tested for or their metabolites. Various chemical agents, such as EDTA, formic acid, acetic acid, sodium fluoride, lithium heparin, potassium oxalate, and methylacrylate have been used to stabilize analytes in biological matrices. ... 

Lithium FE,SC Green-top Vacutainer specimen tube (may contain lithium heparin) can cause marked elevation (up to 6-8 mEq/L). 

Osmolality Osm Lavender-top (EDTA) Vacutainer specimen tube (15 mOsm/L) gray-top (fluoride-oxalate) tube (150 mOsm/L) blue-top (citrate) tube (10 mOsm/L) green-top (lithium heparin) tube (theoretically, up to 6-8 mOsm/L). 

Heparin ammonium Heparin lithium Heparin sodium SPL Heparin Ammonium SPL Heparin Lithium SPL Heparin Sodium USP 232-683-8 Glycogen Pentagen 232-685-9 Amylose 232-686-4 Amylodextrin C AraTex C BatterCrisp C CleanSet C ClearCrisp C ClearSet C DrySet C Gel C HiForm C HiForm-A Covafluid AMD C QuickSet C Set... 

If the analyte is very volatile (e.g., propane or butane) and a quantitative analysis is required, a blood sample should be collected directly into the headspace vial in which the analysis will be carried out. Many other volatile compounds are relatively stable in blood and other tissues if simple precautions are taken. In the case of blood, the container used for the sample should be glass, preferably with a cap lined with metal foil greater losses may occur if plastic containers are used. The tube should be as full as possible and should only be opened when required for analysis and then only when cold (4°C). If the sample volume is limited, it is advisable to select the container to match the volume of blood so that there is minimal headspace. An anticoagulant [sodium ethylenediaminetetraacetate (EDTA) or lithium heparin] should be used. Specimen storage between - 5 and 4°C is recommended and 1% (w/v)... 

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