List the best choice testing method for the following constituents/analytes:
Creatinine
Total Protein Sodium, Potassium, and Chloride
Albumin
Bilirubin
Glucose
The correct answer and explanation is:
Here are the best choice testing methods for the specified analytes:
- Creatinine: Jaffe Reaction (Colorimetric method) or Enzymatic Assay
- Total Protein: Biuret Method
- Sodium, Potassium, and Chloride: Ion-Selective Electrode (ISE) Method
- Albumin: Bromocresol Green (BCG) Dye-Binding Method
- Bilirubin: Diazo Method (Jendrassik-Grof Method)
- Glucose: Glucose Oxidase Method or Hexokinase Method
Explanation
Creatinine:
The Jaffe Reaction is a common colorimetric method where creatinine reacts with alkaline picrate to form a colored complex measurable by spectrophotometry. The enzymatic assay is more specific and less prone to interference, often used in automated analyzers.
Total Protein:
The Biuret method is widely used for total protein estimation. It is based on the formation of a violet-colored complex when proteins react with copper ions under alkaline conditions. This method is reliable and simple.
Sodium, Potassium, and Chloride:
Ion-Selective Electrodes (ISE) are the preferred method for measuring electrolytes because they allow direct and rapid measurement of ion concentrations in biological fluids. The electrodes are selective for each ion, providing precise and accurate results.
Albumin:
The Bromocresol Green (BCG) dye-binding method is the most common assay for serum albumin. Albumin binds to BCG dye forming a green complex, which can be measured spectrophotometrically. This method is sensitive and specific for albumin.
Bilirubin:
The Diazo reaction or Jendrassik-Grof method is used for bilirubin quantification. Bilirubin reacts with diazotized sulfanilic acid to form azobilirubin, which is measured colorimetrically. This method distinguishes between conjugated and total bilirubin.
Glucose:
The Glucose Oxidase method uses the enzyme glucose oxidase to oxidize glucose to gluconic acid and hydrogen peroxide. The hydrogen peroxide is then measured, often by a colorimetric reaction. The Hexokinase method is an enzymatic assay considered more specific and less prone to interference.
These methods are standard in clinical laboratories due to their accuracy, reliability, and compatibility with automated analyzers.