Urinalysis

• Urine


  Biohazardous substance that requires adherence to Standard Precautions
• Urine specimen collection

  1. Collect in clean, dry, leak-proof containers

  2. Disposable containers preferred to avoid contamination

  3. Containers should have wide mouths for easy collection and clear material for color and clarity assessment

  4. Recommended capacity is 50 mL, allowing for various analyses

  5. Sterile containers with secure closures are necessary for microbiologic studies or if there's a delay between collection and analysis

  6. Specially designed sterile containers with transfer devices are available for specific tests
• Urine specimen labels


  • Include patient's name, ID number, date and time of collection, and additional details such as age, location, and healthcare provider's name
  • Labels should be attached to the container, not the lid, and should remain secure even if the container is refrigerated or frozen
• Urine specimen requisitions


  • A requisition form, whether manual or computerized, must accompany specimens to the lab
  • Information on the requisition form must match the details on the specimen label
  • Additional information on the form may include collection method, type of specimen, interfering medications, and patient's clinical information
  • The time of specimen receipt in the laboratory should be documented on the form
• Specimen integrity


  • Specimens should be promptly delivered to the laboratory and tested within 2 hours
  • If unable to test within 2 hours, specimens should be refrigerated or have a suitable chemical preservative added
  • Prolonged storage at room temperature can lead to significant changes in specimen composition, primarily due to bacterial growth
  • Improper preservation can severely affect the accuracy of routine urinalysis results
• Specimen preservation

  1. Refrigeration at 2°C to 8°C is the most common method to decrease bacterial growth and metabolism in urine specimens

  2. For urine cultures, refrigeration should be maintained during transit and until cultured, up to 24 hours. The specimen must return to room temperature before chemical testing

  3. When refrigeration isn't possible for long-distance transport, chemical preservatives may be added

  4. Ideal preservative characteristics: bactericidal, inhibit urease, preserve formed elements, and not interfere with chemical tests
• Random specimen


  • Most commonly collected type, can be collected at any time, but the exact time of collection must be noted
  • Good for basic screening tests, but can give misleading results if the patient has recently eaten or exercised
• First morning specimen


  • Preferred screening sample, essential for preventing false-negative pregnancy tests and evaluating orthostatic proteinuria
  • Concentrated, making it more reliable for detecting certain substances and cells
  • Patients should collect the sample immediately upon waking up and deliver it to the lab within 2 hours or refrigerate it
• 24 hour or timed specimen


  • Provides a more complete picture of a patient's metabolic condition over a longer period
  • Useful for evaluating kidney function, protein excretion, and other conditions that require quantitative measurements
• Urine is continuously produced by the kidneys as an ultrafiltrate of plasma, with approximately 170,000 mL of filtered plasma converted to an average daily urine output of 1200 mL through reabsorption of water and essential substances
• Urine composition

  • Typically 95% water and 5% solutes, subject to variations due to factors like diet, activity, metabolism, and hormones
  • Urea, a metabolic waste product from protein breakdown in the liver, makes up nearly half of urine's total dissolved solids
  • Other organic substances include creatinine and uric acid, while chloride is the major inorganic solid, followed by sodium and potassium
  • Small amounts of various inorganic chemicals are also present, influenced by dietary intake
• Urine may contain hormones, vitamins, medications, and formed elements like cells, casts, crystals, mucus, and bacteria, and elevated levels of formed elements often indicate underlying diseases
• Normally, people pee around 1200 to 1500 mL a day, but anywhere from 600 to 2000 mL is considered normal because everyone's different and different things can affect it
• First morning specimen


  The preferred screening sample, concentrated and more reliable for detecting certain substances and cells
• 24-hour or timed specimen


  Essential for precise quantitative results, as certain urine solutes exhibit variations throughout the day
• 24-hour or timed specimen collection


  Patients must be instructed on the proper collection, starting and ending with an empty bladder
• Catheterized specimen


  Obtained using a sterile technique, where a hollow tube (catheter) is inserted through the urethra into the bladder
• Mid-stream clean catch specimen


  Offers a safer and less invasive way to collect urine for bacterial culture and routine urinalysis, reducing contamination by epithelial cells and bacteria
• Suprapubic specimen


  Urine collected through external insertion of a needle into the bladder through the abdomen, offering a sample for bacterial culture that's entirely free from external contamination
• Prostatitis specimen collection (Three-Glass Collection)

  1. The area is cleansed using the male midstream clean-catch procedure

  2. The first urine passed is collected instead of being discarded

  3. The midstream portion is collected in a separate container

  4. The prostate is massaged to release prostate fluid, collected in a third container
• Prostatitis specimen collection (Pre- and Post-Massage Test)

  1. A clean-catch midstream urine specimen is collected

  2. A second urine sample is collected after prostate massage

  3. A positive result indicates significant bacteriuria in the post-massage specimen, exceeding the pre-massage count by more than 10 times
• Pediatric specimen collection (Routine)

  1. Soft, clear plastic bags with hypoallergenic adhesive are used for routine collections in both boys and girls

  2. Care is taken not to touch the inside of the bag when applying it

  3. Ensure the genital area is free from contamination before attaching the bag firmly, avoiding contact with the anus

  4. Once enough specimen is collected, the bag is removed and labeled, or the specimen is poured into a container following institutional policy
• Pediatric specimen collection (Sterile)


  1. Sterile specimens can be obtained through catheterization or suprapubic aspiration

  2. For catheterization or aspiration, the area is cleaned with soap and water and then dried sterilely to remove any soap residue

  3. A sterile bag is firmly applied, and the collected specimen is transferred into a sterile container and labeled accordingly
• Drug specimen


  Chain of custody documentation process ensuring sample identification from collection to laboratory analysis, involving collectors, couriers, medical review officers, and employers
• Drug specimen labeling and transportation


  Specimens labeled, packaged, and transported according to laboratory-specific instructions
• Urinalysis testing
• Tamper Prevention


  Ensures no substitution, adulteration, or dilution of specimens; Proper handling by authorized personnel with secure access
• Tamper Prevention


  Ensures no substitution, adulteration, or dilution of specimens.

  Proper handling by authorized personnel with secure access.
• Chain of Custody


  Documentation process ensuring sample identification from collection to laboratory analysis.

  • Involves collectors, couriers, medical review officers, and employers.
• Identification Requirement 


  Photo identification or positive identification by an employer representative with photo ID.

  • Witnessed vs. Unwitnessed Collections:
  • Witnessed collections for suspected tampering or per client policy.
  • Same-gender collector observes urine collection.
• Temperature Verification 


  Temperature checked within 4 minutes of collection (32.5°C to 37.7°C)
• Urine Color Inspection


  Assesses for signs of contaminants before labeling and packaging
• Labeling and Transportation


  Specimens labeled, packaged, and transported according to laboratory- specific instructions