AUBF/L PRELIMS-GLUCOSE, KETONES & REDUCING SUGARS

Glucose Oxidase and Peroxidase

Double sequential enzyme reaction used in reagent strips

Urine Temperature, pH and Specific Gravity

Factors that affect the sensitivity of the reagent strip

False Negative

Presence of Ascorbic Acid at a concentration of ≥50 mg/dL would result to this in the reagent strip

Sodium Hypochlorite & Peroxidase

Results to a False Positive reactions in the reagent strip

Benedict’s Test

performed to detect presence of reducing sugars; results vary from blue to green to orange

Copper Sulfate, Sodium Carbonate, Sodium Citrate Buffer

Composition of Benedict’s Reagent

Fehling’s A

Cupric Sulfate in distilled water

Fehling’s B

Rochelle Salt

Sodium Potassium Tartrate, Sodium Hydroxide, Distilled H2O

Composition of Rochelle Salt

Fehling’s Test

depends on the ability of glucose and other reducing sugars to reduce cupric hydroxide to cuprous hydroxide

Yellow Precipitate; Absence of Yellow Precipitate

Positive result/Negative result of Fehling’s Test

Haine’s Test

depends on the ability of glucose and other reducing sugars to reduce cupric hydroxide to cuprous oxide; uses Copper Sulfate, NaOH & Glycerol as reagent

Copper Sulfate, NaOH, Glycerol, Distilled Water

Composition of Haine’s Reagent

Trommer’s Test

depends on the ability of glucose and other reducing sugars to reduce cupric hydroxide to cuprous oxide; uses 10% KOH and 10% Copper Sulfate 

Positive

After using 1mL of 10% KOH and adding 10% Copper Sulfate Solution drop by drop, the medtech shook it until the mixture turned blue. Upon heating the mixture, there is a sudden formation of yellow red precipitate. What is the result?

Nylander’s Test

Reduction of bismuth to metallic bismuth in a hot alkaline solution

Nylander’s Reagent

Uses Rochelle Salt, 10% NaOH or KOH, Bismuth Subnitrate and produces a black color as a positive result

Brown Precipitate

A trace of glucose is seen in Nylander’s Test, What result is expected to be observed?

Moore-Heller’s Test

uses 10% KOH; caramelization of sugars by strong alkali and heat are the basis of the test

Phenylhydrazine Test (Osazone Test)-Glucose

Positive result: fine bright yellow needles arranged in bundles, sheaves or rosettes

Pure Phenylhydrazine, Glacial Acetic Acid and Saturated solution of Sodium Chloride

Kowarsky Phenylhydrazine Test (Blumel’s Modification) reagents

Glucose Oxidase Paper Strip Test

uses o-toluidine as an indicate reagent

Purple color in test area

Positive Result for Glucose Oxidase Paper Strip Test

Ascorbic Acid

False negative result in Glucose Oxidase Paper Strip Test