Field chemistry analysis Vap, Linda M; Weiser, M Glade
The Veterinary clinics of North America. Food animal practice,
11/2007, Volume:
23, Issue:
3
Journal Article
Peer reviewed
Typical manual and automated technologies used in field chemistry testing are reviewed, along with associated advantages and disadvantages. A brief overview of metabolic disease monitoring is ...included. Guidelines for evaluating and achieving success are provided, including criteria for system evaluation and expectations for comparative performance evaluations. The more common problems and limitations associated with field chemistry diagnostics and how to best prevent them are also discussed.
The typical technologies used in veterinary hematology and biochemical analyzers are reviewed, along with associated advantages and disadvantages. Guidelines for implementing a successful in-clinic ...laboratory are provided, including criteria for system evaluation and expectations for comparative performance evaluations. The more common problems and limitations associated with in-clinic laboratory diagnostics and how to best prevent them are also discussed.
Renal disease is a major cause of illness in captive and wild avian species. Current renal disease markers (e.g., uric acid, blood urea nitrogen, and creatinine) are insensitive. Two endogenous ...markers, creatine and N-acetyl-β-D-glucosaminidase (NAG), were selected for study in the pigeon (Columba livia). Representative organs from four pigeons were surveyed to determine those exhibiting the highest level of each marker. In a separate study, NAG and creatine from plasma and urine were assayed before and after gentamicin (50 mg/kg twice daily), administration for up to 9 days. Observer-blinded pathologic scoring (five saline solution controls, 17 treated birds) was used to verify the presence of renal disease that corresponded to marker increases. The first study revealed that kidney tissue had the highest NAG activity (by approximately six times), and pectoral muscle had the most creatine (>900 times). In response to gentamicin, plasma creatine (>five times) and NAG increased (approximately six times), which paralleled uric acid (>10 times). Urine creatine (approximately 60 times) and NAG increased dramatically (approximately 50 times) in response to gentamicin. In conclusion, NAG, especially in the urine, may be of value to noninvasively detect renal toxin exposures and to monitor potentially nephrotoxic drugs, and might be of value to screen free-ranging birds in large exhibits or in the wild by assaying fresh urate samples at feeding stations.
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: The concentration of chloride ions in rumen fluid is a useful measure of obstructive gastrointestinal disease in ruminants and camelids. However, rumen fluid is very different from other biological ...fluids in its bacterial populations, consistency, and concentrations of various anions. Two methods of determining the chloride concentration in biological fluids were compared using centrifuged and filtered rumen fluid containing different amounts of sodium chloride. Although coulometric titration and potentiometric electrode analysis yielded results that had a strong linear relationship, the results of potentiometry were consistently and significantly higher, by about 20 mEq/L. This difference was investigated further by analyzing a series of fluids containing different concentrations of sodium acetate. Acetate was detected as chloride (0.21 chloride molecules per acetate molecule) by potentiometry but not by coulometric titration. Therefore, the acetate concentration of rumen fluid was the most likely cause of the discrepancy between tests in the original trial. In conclusion, the coulometric procedure may be more accurate than the potentiometric procedure for measuring rumen chloride when the concentrations of possible confounding ions are unknown.
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17.
An update on chemistry analyzers Vap, L M; Mitzner, B
The Veterinary clinics of North America. Small animal practice,
09/1996, Volume:
26, Issue:
5
Journal Article
Peer reviewed
This update of six chemistry analyzers available to the clinician discusses several points that should be considered prior to the purchase of equipment. General topics include how to best match an ...instrument to clinic needs and the indirect costs associated with instrument operation. Quality assurance recommendations are discussed and common terms are defined. Specific instrument features, principles of operation, performance, and costs are presented. The information provided offers potential purchasers an objective approach to the evaluation of a chemistry analyzer for the veterinary clinic.
To compare results for sodium and potassium determination on llama urine, using flame emission spectrophotometry (flame photometry), atomic absorption spectrophotometry (AAS), indirect ion-selective ...electrode potentiometry (ISE), and direct ISE.
Llama urine samples encompassing a wide range of electrolyte concentrations were analyzed for sodium and potassium concentrations, using 4 analytical methods, and results were compared statistically to assess correlation, bias, and potential interferents.
10 healthy male llamas.
Urine specimens were obtained from llamas fitted with urine collection apparatus at defined intervals over a 24-hour period. Urine samples were centrifuged, and supernatants were frozen at -70 C until analysis. Analytical procedures were done, using standard laboratory protocols. Means, correlation coefficients, and bias were calculated, and differences were evaluated by ANOVA, with significance set at P < 0.05.
There was strong correlation and good agreement among sodium values obtained by flame photometry, AAS, and indirect ISE. Sodium values obtained by use of direct ISE correlated poorly with other methods; urine is not an acceptable specimen for this method. Only AAS and indirect ISE had good correlation (r > 0.9) for potassium values. Data did not suggest presence of a potassium chelator in llama urine; urine potassium values measured by indirect ISE were significantly higher (by 150 to 200 mmol/L) than those measured by other methods.
Urine electrolyte analysis in llamas resulted in less agreement between methods than is generally found for serum. Data collection for patient monitoring or research analysis should be restricted to a single method to avoid differences in results attributable to analytical variance.
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