Urinalysis and Body Fluids Exam 1 Study Guide

Quality Assurance (QA) Definition: Guaranteeing good patient care?
Quality Control (QC) Definition: Are your methods providing results as they should be?
Frequency of Quality Control Performance: Once per day of testing
Minimum Number of QC Levels: Two levels
Protocol for Out-of-Control QC:
- Patient results cannot be reported if QC is out of range.
Qualitative vs. Quantitative Definitions:
- Qualitative: Testing that determines the presence or absence of a substance (e.g., positive or negative).
- Quantitative: Testing that determines the exact amount or concentration of a substance (e.g., $150\,mg/dm^3$ ).

Value of Urinalysis in Patient Testing: Noninvasive means to evaluate kidney function, Easily collected, Inexpensive
Normal Components of Urine: Primarily water ( $95\%$ ) and solutes ( $5\%$ ) such as urea, creatinine, sodium, potassium, and chloride.
Sterility of Urine: Urine is generally considered sterile while in the bladder
Collection Methods and Types of Urine Samples:
- Random Urine: Collected at any time. Used for routine screening. Most likely to be contaminated (least sterile).
- Catheterized Urine: Collected via a sterile tube inserted into the bladder. Used for bacterial cultures and patients unable to void. This is one of the cleanest and most sterile collection methods.
- First Morning Sample: It is highly concentrated
- Midstream Clean-Catch: Patient cleans the area and catches the urine mid-stream to minimize contamination from skin flora.
Catheterized: May contain epithelial cells due to the trauma of the catheter insertion.

Testing Window: Urine should ideally be tested within $2\,hours$ of collection if it is not preserved.
Effects of No Preservation (Time Delay):
- Color: May darken due to the oxidation of metabolites.
- Clarity: Decreases as bacteria multiply and crystals precipitate.
- Odor: Becomes ammonia-like due to bacterial breakdown of urea.
- pH: Increases (becomes more alkaline) as bacteria convert urea to ammonia.
- Glucose: Decreases due to glycolysis by bacteria.
- Bacteria: Population increases significantly due to multiplication.
Refrigeration of Urine:
- Temperature: Required at $2-8\,^{\circ}C$ .
- Value: Is that it’s simple
- Disadvantage (Crystals): Refrigeration causes the precipitation of amorphous phosphates and urates, which can obscure microscopic examination.
Chemical Preservatives:
- Advantages: Stabilize specific chemical analytes.
- Disadvantages: Can cause drug and hormone interferences or interfere with chemical reagent strip reactions.

Components of Physical Examination: Color, Clarity, Odor, Volume, Specific Gravity, and Osmolality.
Yellow Color Source: The pigment urochrome
Color as an Indicator of Hydration: Pale yellow indicates overhydration or dilute urine; dark yellow/amber indicates dehydration.
Pathological vs. Non-Pathological Colors:
- Pink: Uroerythrin
- Orange/Orange-Brown:
  - Non-Pathological: Old samples (oxidation) or Pyridium (Azo meds for UTI).
  - Pathological: Bilirubin (often accompanied by yellow foam).
- Neon Yellow: Non-Pathological (B vitamins or asparagus).
- Green:
  - Pathological: Pseudomonas infection.
- Red:
  - Non-Pathological: Diet rich in beets.
  - Pathological: Presence of intact RBCs (hematuria) or hemoglobin (hemoglobinuria).
- Port Red (Burgundy/Wine): Porphyrias
- Brown-Black: Pathological (melanins due to melanoma).
- Black: Pathological (homogentisic acid due to Alkaptonuria).
Foam Observations:
- No foam: Normal.
- White foam: Protein.
- Orange foam: Bilirubin.
Follow-up Testing: Color observations must be referenced against Chemistry & Microscopy to verify pathological status.

Measures of Concentration: Concentration measures the amount of solute present in a given volume of solution. Common measures include:
- Molarity (M): mols/L
- Molality (m): mols/kg

Specific Gravity (SG):
- Normal Range: Typically $1.003$ to $1.035$ .
- Non-Urine Readings: Values above $1.040$ usually indicate radiographic dyes (X-ray contrast).
- Renal Failure: Often results in isosthenuria, where the SG is fixed at $1.010$ .
Correction Formula for Refractometer: glucose and urine & add formua
- The SG must be corrected for high levels of protein or glucose which contribute to the refractive index but not necessarily renal concentrating ability.
Osmometry and Colligative Properties:
- Colligative Properties: Properties of a solution that depend on the number of solute particles, not their identity (e.g., freezing point depression).
- Contributing Components: Sodium, chloride, and urea are the primary contributors to urine osmolality.
- Normal Urine Osmometry: Ranges from $50\,mOsm/kg$ to $1200\,mOsm/kg$ .
- Abnormally High: Caused by dehydration or the presence of high-molecular-weight substances (e.g., glucose).
- Abnormally Low: Caused by excessive fluid intake or conditions like Diabetes Insipidus where the kidneys cannot concentrate urine.