Body Fluid Collection Processes and Analyses

Body Fluid Collection Processes

• Lumbar Puncture (CSF): A needle is inserted into the lumbar region to collect cerebrospinal fluid (CSF).
• Thoracentesis (Pleural Fluid): A needle is inserted into the pleural space to collect pleural fluid.
• Pericardiocentesis (Pericardial Fluid): A needle is inserted into the pericardial sac to obtain pericardial fluid.
• Paracentesis (Ascites): A needle is inserted into the peritoneal cavity to remove accumulated peritoneal fluid (ascites).

Laboratory Departments and Analyses

• Hematology: Analyze blood components, including cells and counts.
• Clinical Chemistry: Measures various substances in body fluids, such as glucose and protein concentrations in urine and other samples.
• Microbiology: Examines for infectious agents through staining techniques (e.g., Gram stain) and cultures on body fluids like urine.
• Cytology/Pathology: Examines cell structure and function for signs of abnormality in body fluids.

Primary Solutes in Normal Urine

• Urea
• Creatinine
• Uric acid
• Chloride
• Sodium
• Potassium
• Phosphate
• Ammonium
• Calcium

Basic Urine Composition

• Urine consists of water, urea, organic chemicals, and inorganic chemicals.

Average Daily Urine Volume

• A normal adult produces 1200-1500 mL of urine daily.

Changes in Urine After Sitting at Room Temperature

• Urine color changes
• Clarity decreases
• Glucose, ketones, bilirubin, urobilinogen, trichomonas, red blood cells (RBCs), white blood cells (WBCs), and casts increase.
• Odor, pH, nitrite, and bacteria increase.

Urine Specimen Collection Techniques

• Midstream Clean Void: Minimizes contamination by starting urination, then collecting a midstream portion of the sample.
• Catheterization: A catheter is inserted into the urethra to collect a urine sample directly from the bladder.
• Suprapubic Aspiration: A needle is inserted through the abdomen to collect urine directly from the bladder.
• Pediatric Collection Bags: Use bags attached to the genital area for children.
• Random Void: A sample collected at any time, often used for routine screening tests.
• First Morning Void: Ideally suited for tests requiring a concentrated sample, useful for pregnancy and proteinuria.
• Timed (24-Hour): A 24-hour collection to measure the total amount of certain substances in urine.

Urine Volume Terminology

• Oliguria: Decreased urine output.
• Anuria: No urine production.
• Nocturia: Increased urine production at night.
• Polyuria: Increased urine excretion.

Urine Preservation Methods

• Refrigeration
• Boric acid
• Formalin
• Sodium fluoride
• Commercial preservative tablets

Requisition Definition

• A formal order/request for use of materials/resources.