Reagent Test Strip Reactions Based on three principles: 1. Colorimetric: substance in urine plus key color = visible reaction 2. Enzymatic: enzymes breakdown specific compounds = visible reaction 3. Catalytic: substance in urine causes reaction to proceed = visible reaction

Reagent Test Strips Two different types of information result: 1. Qualitative: positive or negative 2. Quantitative: how much (mg/dl, 4 plus, etc.)

Reagent Test Strips Run a positive and negative control daily Record results Repeat if controls are out of range Date bottles when received and when in use QC new Lot #’s of reagents and strips

Reagent Strip Technique Dip briefly into RT, mixed, uncentrifuged urine Touch edge to remove excess Wait specified time Compare color reaction to chart

Storage of Test Strips Protect from moisture, volatile chemicals, heat and light I.E Room Temperature <30 C Desiccated opaque container

Test Strip QC Check with Positive and Negative control at least daily and whenever a new bottle of strips is opened. Questionable results are obtained

Affects of Improper Technique Leaving strip in urine too long Failure to remove excess urine from strip Failure to wait proper amount of time Wrong color chart Failure to test urine at RT False neg Chemicals leach from pads Runover pH protein False Neg LE Incorrect Correlation False Neg Enzymatic reactions require proper Temp

How are Reagent Strips protected from deterioration caused by: Moisture Volatile chemicals Light heat Dessicant Keep container closed!! Close container Do not use in presence of fumes Opaque containers Temp < 30 C