Term
| Perform the Berthelot method for determining urea nitrogen via a manual kit by Stanbio |
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Definition
Berthelot methods are where urea in the sample is hydrolyzed by the enzyme urease to yield ammonia and carbon dioxide, phenol is replaced by salicylic acid. Ammonium ions react with Salicylate, sodium nitroprusside, and hypochlorite to yield a blue-green. Absorbance is proportional to urea concentration.
Add enzyme reagent to tubes, blank at 600nm with DI water, add appropriate liquid to tubes, cover, and mix and incubate. Add color reagent to the tubes, cover, and mix and incubate. Read and record absorbance, convert to concentration via Beer’s law. |
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Term
| Identify interfering substances for Berthelot method for determining urea nitrogen |
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Definition
| Ammonia contamination of glassware or water, fluorides at concentrations above 5 mg/dL, drugs and metabolites |
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Term
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Definition
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Term
| Principle of Berthelot method for determining urea nitrogen |
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Definition
| The principle of the method is to introduce students to the berthelot method for the quantification of urea nitrogen in serum |
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Term
| If your controls were not within the expected range, explain what you would do |
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Definition
| If the controls were not within the expected range then the patient’s results could not be released. The controls would have to be remade, or the spectrophotometer would have to be adjusted. |
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Term
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Definition
| 38.7 mg/dL / 5.8 mg/dL= 6.67, 6:1 |
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Term
| List two disease states causing increased BUN concentration |
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Definition
| Two disease states that can cause increased BUN concentration are shock and congestive heart failure. |
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Term
| List two disease states causing increased creatinine concentration. |
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Definition
| Two disease states the can cause increased creatinine concentration are diabetes and kidney disease |
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Term
6. Given the following laboratory information on an average size adult, calculate a 24-hour creatinine clearance:
Urine creatinine = 140 mg/dl
Serum creatinine = 1.8 mg/dl
Urine volume for 24 hours = 1610 ml |
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Definition
CrCl = Urine Volume for 24 hours x Urine Creatinine / Serum Creatinine
CrCl = 1610 ml/1440 min x 140 mg/dL / 1.8 mg/dL = 156.5/1.8 = 87 mL/min |
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Term
| List two non-protein nitrogen (NPN) substances in blood and give their biochemical origin (the chemical they are immediately derived from). |
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Definition
| Two non-protein nitrogen substances in blood are ammonia and uric acid. Ammonia is due to the breakdown of amino acids and uric acid is the final end of purine catabolism |
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Term
| In the Jaffe reaction, a red orange chromogen is formed when creatinine reacts with |
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Definition
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Term
| Perform the Jaffe method for determining creatinine via a manual kit by Stanbio |
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Definition
The Jaffe reaction is where red-orange color forms when the metabolite is treated with alkaline picrate. Excess picric acid is used to deproteinize the sample to develop the jaffe chromogen on addition of alkali. The absorbance of the compound formed is proportional to creatinine concentration
Add working reagent to each tube a pre warm. Blank with DI water at 510 nm. Add appropriate fluid to the tube and read absorbance at 20 seconds and then 60 seconds. Calculate the change in absorbance (A2-A1) and then repeat with the next liquid. |
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Term
| Identify interfering substances Jaffe method for determining creatinine |
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Definition
| Bilirubin, drugs and other substance |
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Term
| Principle of the Jaffe Method |
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Definition
| The principle is to introduce students to the Jaffe method for the quantification of creatinine in serum. |
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