Glucose Oxidase Reagent Set Analysis

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Questions and Answers

Which of the following analogs can be oxidized by Cholesterol Oxidase, affecting test specificity?

Cholesterol

Dihydrocholesterol (correct)

Beta-sitosterol

Triglycerides

What is the purpose of the TC - Multi Purpose Calibrator in the assay?

To increase absorbance readings

To enhance reagent stability

To calibrate the spectrophotometer

To replace the Cholesterol Standard (correct)

At what wavelength should the spectrophotometer be zeroed before recording absorbances?

550 nm

520 nm (correct)

450 nm

400 nm

What is the linearity limit of the cholesterol reagent indicated in the content?

500 mg/dl Signup and view all the answers

What is the recommended storage temperature for the Cholesterol Standard?

2 - 8°C Signup and view all the answers

Which of the following is NOT a component of the Cholesterol Reagent as described?

Triglyceride Oxidase Signup and view all the answers

What should be the incubation temperature for the test tubes after adding the sample?

37°C Signup and view all the answers

What is the pH of the buffer used in the Cholesterol Reagent?

6.8 Signup and view all the answers

What is the intended use of the cholesterol reagent set?

For the quantitative determination of total cholesterol in human serum. Signup and view all the answers

Which of the following statements is true regarding specimen collection for cholesterol testing?

Test specimens should be serum and free from hemolysis. Signup and view all the answers

Which factor can potentially influence cholesterol levels in the serum?

Hepatic thyroid diseases. Signup and view all the answers

In the enzymatic technique developed by Allain et al., what is the role of hydrogen peroxide?

To facilitate the oxidation of cholesterol. Signup and view all the answers

What should be done if turbidity occurs in the reagent?

It indicates possible contamination, and the reagent should be discarded. Signup and view all the answers

What is the proper storage temperature for the reagent set?

At refrigerator temperature (2 - 8°C). Signup and view all the answers

Which chemical is used in place of phenol to improve absorbance in this cholesterol assay?

p-hydroxy benzene sulfonic acid (p-HBS). Signup and view all the answers

What is the normal range for total cholesterol in serum?

100 - 200 mg/dl. Signup and view all the answers

What should be done with samples that have values above 500 mg/dl?

Dilute 1:1 with isotonic saline and multiply the final result by two. Signup and view all the answers

Why is a 'sample blank' required for grossly lipemic serums?

To adjust for interference caused by lipids in the serum. Signup and view all the answers

What calculation is used to determine the concentration of a patient based on absorbance?

A(patient) x Concentration of standard ÷ A(standard) = Concentration of patient. Signup and view all the answers

What does the quality control process in assays typically involve?

Using commercially available control with established values. Signup and view all the answers

How can laboratories establish a normal range for cholesterol values?

By conducting their own tests and determining a range based on their results. Signup and view all the answers

What might indicate a problem in the assay process according to quality control guidelines?

Obtaining values consistently higher than expected. Signup and view all the answers

What is the recommended dilution method for samples with hyperlipidemia?

Dilute 1:1 with isotonic saline and re-run the assay. Signup and view all the answers

What role does absorbance play in determining cholesterol concentration?

It is used to calculate the deviation from standard values. Signup and view all the answers

Study Notes

Glucose (Oxidase) Reagent Set (Phenol Free)

Intended use: Quantitative determination of total glucose in serum.
Storage: Dry reagent and standard are stored at 2-8°C prior to reconstitution. Reconstituted reagent is stable for 30 days when stored at 2-8°C.
Stability: Reagent can be used until expiration date on packaging.
Specimen collection: Serum samples, free from hemolysis, are recommended. Plasma may not be used if anticoagulants are present.
Interfering substances: Grossly lipemic or icteric sera may cause false glucose values and require a serum blank correction in the analysis.
Procedure limitations: Reagent is linear to 500 mg/dL. Samples exceeding 500 mg/dL require 1:1 dilution with water, followed by recalculation of test results.
Materials required (not provided): Pipettes, test tubes, timer, 37°C heating block/water bath and spectrophotometer.
Procedure (Manual): Prepare reagent, label tubes (blank, standard, control, patient), pipette 1.0 ml working reagent to all tubes, pre-warm in 37°C heating bath, add 10µl sample to each tube, mix, and incubate at 37°C for 10 minutes, zero spectrophotometer with reagent blank at 500nm, and read absorbances.

Cholesterol Reagent Set (Phenol Free)

Intended use: Quantitative determination of total cholesterol in human serum.
Storage/Stability: Stored at refrigerator temperature (2-8°C), ready to use format. When reconstituted, the reagent is stable for 60 days at 2-8°C.
Specimen collection: Serum, free from hemolysis, is preferred. Samples are stable for 7 days at room temperature or 6 months when frozen.
Interfering Substances: Fluoride and oxalate can cause false low values. Hemoglobin levels up to 200 mg/dL, and bilirubin levels up to 10 mg/dL do not interfere. Grossly lipemic or icteric specimens require the use of a serum/plasma blank.
Materials required (not provided): Spectrophotometer, test tubes, pipettes, timer, 37°C heating block.
Procedure (manual): Pre-warm reagent at 37°C for 2 minutes, add sample, incubate for 10 minutes at 37°C, zero spectrophotometer, and record absorbance at 520 nm.

Triglyceride Reagent

Intended use: Quantitative determination of triglycerides in serum or plasma.
Storage: Stored at 2-8°C.
Specimen collection: Fresh, clear, non-hemolyzed serum from fasting patients is recommended. Stable for 3 days at 2-8°C when refrigerated or 6 months when stored and frozen properly.
Interferences: Grossly lipemic or icteric samples, and high bilirubin or hemolysis may cause false results. Glycerol in collection tube stoppers may interfere. Avoid using collection tubes with glycerol lubrication.
Materials required (not provided): Spectrophotometer, test tubes, pipettes, hot bath/incubator (37°C), timer.
Procedure: Add reagent, add sample, incubate, and measure absorbance at 520nm.

Urea Nitrogen (BUN) Reagent

Intended use: To determine the level of urea nitrogen in serum.
Storage: Stored at 2-8°C before reconstitution. Reconstituted reagents are stable for 2 days at room temperature (18-25°C) or 21 days at 2-8°C.
Specimen collection: Serum is preferred, avoiding hemolysis. Stable for 72 hours when refrigerated, and 8 hours without refrigeration.
Interferences: Anticoagulants containing fluoride, citrate, or EDTA can inhibit urease and should be avoided. High ammonia levels in water or other substances may cause false elevations and should be avoided.
Materials required (not provided): Pipettes, test tubes, timer, water, spectrophotometer.
Procedure (manual): Reconstitute reagent, label tubes, add 1.0 ml of reagent to each tube, pre-heat to 37°C, add sample, incubate for 60 seconds, read absorbance at 340nm.

Creatinine Reagent

Intended use: Quantitative determination of creatinine in serum.
Storage: Stored at room temperature(15-30°C). Combined reagent is stable for 1 month.
Specimen collection: Serum samples. Stable for 24 hours when refrigerated or several months when properly frozen.
Interferences: Potential interferences from albumin, moderate hemolysis, high levels of icterus or lipemia, or acetoacetate.
Materials required (not provided): Pipettes, test tubes, 37°C water bath/incubator, spectrophotometer.
Procedure (manual): Label tubes, add reagent and sample, incubate at 37°C, zero spectrophotometer with reagent blank, read absorbance at 510nm.

Uric Acid Reagent

Intended use: To quantify serum uric acid.
Storage: Stored refrigerated. Do not freeze.
Specimen collection: Serum is preferred, free from hemolysis. Stable for 3 days refrigerated , or months when frozen.
Interferences: Bilirubin, ascorbic acid, lipemia.
Materials required (not provided): Reagent blank, sample tubes, pipettes, timer, spectrophotometer (with a 37°C heating block/water bath).
Procedure (manual): Warm reagents in a 37°C water bath, Label tubes, Add reagents, Add samples, Incubate at 37°C for 10 minutes, zero at 510nm, read absorbance.

Direct LDL Cholesterol Reagent

Intended use: Quantitative determination of LDL cholesterol in serum or plasma.
Storage/Stability: Liquid reagents, stored at 2 to 8 degrees Celsius
Materials required (not provided): Automatic chemistry analyzer or spectrophotometer, calibration fluid, LDL controls.
Procedure (automated or manual): Automated protocol specified by the instrument manufacturer. Manual protocol includes the use of two reagents, and incubation at 37C

Direct HDL Cholesterol Reagent

Intended use: Quantitative determination of HDL cholesterol in serum or plasma.
Storage/Stability: Liquid reagents, stored at 2 to 8 degrees Celsius
Materials required (not provided): Automated chemistry analyzer or spectrophotometer, calibration fluid, HDL controls.
Procedure (automated or manual): Automated protocol specified by the instrument. Manual procedure involves preparation of reagents incubation at 37C, and absorbance readings

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Description

This quiz covers the usage and procedures for the Glucose Oxidase Reagent Set intended for quantitative determination of glucose in serum. Topics include specimen collection, storage conditions, and limitations of the procedure. Test your knowledge on handling and interpreting results based on serum samples.