Urobilinogen Testing Methods Overview

What is the principle behind the Multistix test method?

Which substance is NOT reliably detected by the Ehrlich reagent-based method in Multistix?

How does the Chemstrip method differ from the Multistix method?

What color indicates the presence of urobilinogen in the Multistix method?

What is the normal range of urobilinogen levels detected by Multistix?

Which condition can lead to false results in both Multistix and Chemstrip tests?

Why is a freshly voided sample preferred for urobilinogen testing?

What is the detection capability of the Chemstrip urobilinogen test?

What will the Chemstrip method produce in the presence of urobilinogen?

What condition might lead to an unreliable detection of urobilinogen?

Reagent Strip Methods for Urobilinogen Testing

Multistix Method: Employs the Ehrlich aldehyde reaction. The test area contains an acid buffer and p-dimethylaminobenzaldehyde. Urobilinogen reacts to form reddish brown color. Normal range is 0.2-1 mg/dL.
Color Range: Light yellow to red-brown.
Limitations: Not specific for urobilinogen. Detects other substances reacting with Ehrlich reagent: porphobilinogen, p-aminosalicylic acid metabolites, sulfonamides, procaine, 5-hydroxyindoleacetic acid, indole, methyldopa. Not reliable for porphobilinogen.
Chemstrip Method: Uses 4-methoxybenzene-diazonium-tetrafluoroborate, which forms a red azo dye with urobilinogen in an acidic environment.
Detection Limit: Approximately 0.4 mg/dL.
Reading Time: Results are read within 10-30 seconds.
Specificity: Unlike Multistix, Chemstrip is more specific for urobilinogen.

Factors Affecting Reagent Strip Tests

Sample Stability: Freshly voided urine is preferred as urobilinogen is unstable and can form non-reactive urobilin in acidic urine.
Drug Interference: Metabolites of drugs like phenazopyridine (Pyridium) and Azo-Gantrisin can affect the tests by causing false positives or masking the reaction with urobilinogen (changing the urine color, for example).
Other Interferences: Bilirubin and blood usually do not interfere but bilirubin can sometimes cause a green color.

Explore the different reagent strip methods for testing urobilinogen, including the Multistix and Chemstrip methods. Learn about their specific reactions, limitations, and color ranges. This quiz provides an insight into factors that affect reagent strip tests for urobilinogen detection.