l1 Flashcards
What is urine?
An ultrafiltrate of plasma
Urine is produced by the kidneys and is primarily composed of water and solutes.
What is the normal composition of urine?
95% water, 5% solutes
Solute variations can occur due to diet, activity, metabolism, endocrine factors, and body position.
What is the major organic solute in urine?
Urea
Urea is derived from the metabolism of amino acids and accounts for 60%-90% of nitrogenous material in urine.
What are the typical amounts of urea, creatinine, and uric acid in urine?
- Urea: 25.0-35.0 g
- Creatinine: 1.5 g
- Uric Acid: 0.4-1.0 g
These values can vary based on diet and health.
Define anuria.
Cessation of urine flow
This condition indicates severe kidney damage or decreased renal blood flow.
What is oliguria?
Decrease in urine output
Defined as less than 1 ml/kg/hr for infants, less than 0.5 ml/kg/hr for children, and less than 400 ml/day for adults.
What is nocturia?
Increased urine excretion at night
Normally, urine excretion is 2-3 times more during the day.
Define polyuria.
Increase in daily urine volume
Associated with conditions like diabetes mellitus and can be artificially induced by diuretics, caffeine, and alcohol.
What is the usual daily urine volume?
1200-1500 mL
The normal range for urine volume is between 600-2000 mL.
What are the grounds for urine specimen rejection?
- Unlabeled containers
- Non-matching labels and requisitions
- Contaminated specimens
Laboratories have written policies that specify these grounds.
What is the ideal preservative for urine specimens?
Bactericidal, inhibits urease, preserves formed elements, does not interfere with chemical testing
Routine preservation is done through refrigeration, especially for culture specimens.
What is a random urine specimen?
Most common type received, collected at any time
Results may be altered by dietary intake and activity.
What is the purpose of a first morning specimen?
Ideal screening specimen due to its concentration
It is collected immediately upon rising and delivered to the lab within 2 hours.
What is a fasting specimen?
Second specimen voided after fasting for 8 hours
This specimen is recommended for glucose monitoring.
What does a 2-hour postprandial specimen monitor?
Insulin therapy
Results can be compared with fasting urine specimen and blood test results.
What is the principle of a refractometer?
Measures the refractive index of urine
It determines the concentration of solutes by measuring the velocity of light passing through the solution.
What does urine clarity refer to?
Transparency or turbidity of a specimen
Normal reporting includes clear, hazy, cloudy, turbid, and milky.
What does the color of urine indicate?
Varies from almost colorless to black
Abnormal colors suggest bleeding, liver disease, or infection.
What is the typical odor of fresh urine?
Faintly aromatic
Older urine can smell like ammonia, while certain metabolic disorders can produce distinctive odors.
What is the significance of urine specific gravity?
Indicates urine concentration
Changes in specific gravity can reflect hydration status.
What is the procedure for determining urine color and clarity?
Use a well-mixed specimen, view against a white background
Maintain adequate room lighting for accurate evaluation.
What is the procedure for a midstream clean-catch specimen?
Wash hands, clean genitalia, void into toilet first, then into container
This method minimizes contamination.
What is the purpose of a chain of custody in drug specimen collection?
Documentation from collection to lab results
It ensures the specimen’s integrity and withstands legal scrutiny.
What is the principle behind a refractometer?
Refractive Index
Measures velocity of light in air versus velocity of light in a solution.
What are the advantages of using a refractometer?
- Temperature compensation not needed
- Small specimen size: 1 or 2 drops
- Less affected by particle size
What is the methodology for using a refractometer?
- Drop of urine placed on prism
- Focus on light source, and read scale
- Wipe off prism between specimens
What is the routine chemical examination of urine primarily conducted with?
Reagent strips consisting of chemical-impregnated absorbent pads.
What parameters are typically assessed in a routine urine chemical examination?
- Protein
- pH
- Glucose
- Specific gravity
What are the two major types of reagent strips?
- MULTISTIX (Siemens Healthcare Diagnostics)
- CHEMSTRIP (Roche Diagnostics)
Fill in the blank: Reagent strips provide a _______ analysis.
semi-quantitative
What steps should be followed in the reagent strips technique?
- Dip strip briefly into specimen
- Remove excess urine
- Blot edge of strip
- Wait specified time
- Compare color reaction to manufacturer’s chart
True or False: Enzyme reactions on reagent strips are based on room temperature readings.
True
What is required for quality control of reagent strips?
- Run positive and negative controls at least once per 24 hours
- Record control results
What is the purpose of the Watson-Schwartz differentiation test?
Differentiation among urobilinogen, porphobilinogen, and Ehrlich reactives.
What types of cells are identified in a microscopic examination of urine?
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Epithelial cells
What are the types of casts identified in urine microscopy?
- Hyaline
- Cellular cast
- Granular (Coarse / fine)
- Waxy
What is the ideal centrifugation time and speed for urine sediment preparation?
5 min at relative centrifugal force (RCF) of 400.
What should be done post-centrifugation to handle urine specimens?
- Aspirate rather than pour off urine
- Mix sediment gently
What is the minimum volume of urine required for sediment examination?
10–15 mL
What are the types of stains used in microscopic examination of urine?
- Sternheimer-Malbin
- Toluidine Blue
- Gram Stain
- Hansel Stain
- Prussian Blue Stain
What is the function of the Sternheimer-Malbin stain?
Identifies WBCs, epithelial cells, and casts.
What is fecalysis primarily used for?
Examination of stool specimens for ova and parasites.
What is the smallest acceptable amount of stool required for parasitic study?
2 to 5 grams or pea size.
What precautions should be taken to avoid contamination during stool collection?
- Use a clean, dry, sterile wide-mouthed container
- Avoid urine contamination
- Do not retrieve stool from toilet bowl water
How soon should a freshly collected stool sample be submitted to the laboratory?
Within 1 hour after collection.
Fill in the blank: The typical stool collection protocol consists of _______ specimens.
THREE
What should be included on the specimen container label?
Patient’s name, identification number, physician’s name, and date/time of collection.
What is the ideal time for transporting a specimen to the laboratory after collection?
Within 1 hour after collection
What should be included in the labeling of a specimen container?
Patient’s name, identification number, physician’s name, date and time of sample collection
What type of bag should specimens be placed in for transport to the laboratory?
ZIP LOCK PLASTIC BAG
What is the recommended time frame for examining liquid stool specimens?
Within 30 minutes of passage
How many stool samples should be examined before excluding parasites?
Three samples
What is the daily stool weight threshold for diagnosing diarrhea?
> 200 g stool weight per day
What are the mechanisms of diarrhea?
- Secretory
- Osmotic
- Altered motility
What indicates sugar malabsorption in fecal testing?
pH <5.6
Name one cause of secretory diarrhea.
Microbial infections such as E. coli or Vibrio cholerae
What is osmotic diarrhea caused by?
Incomplete digestion or reabsorption of food
What is a common symptom of altered motility in diarrhea?
Irritable bowel syndrome
What is the purpose of the direct fecal smear (DFS) technique?
To study living parasites such as motile protozoa and helminth eggs
What is the significance of fecal leukocytes in stool examination?
> 3 Neutrophils/hpf is significant
What does a fecal occult blood test detect?
Hidden blood in stool
What color indicates blood from the upper GI tract in feces?
Black, tarry
What is the principle behind the fecal occult blood test?
Pseudoperoxidase activity of hemoglobin
What dietary restrictions should be followed before a fecal occult blood test?
- No red meat
- No horseradish
- No melons
- No raw broccoli, cauliflower, radishes, turnips
- No aspirin or anti-inflammatory agents for 7 days
- Avoid vitamin C and iron for 3 days
What is the function of the seminal vesicles in semen production?
Provide nutrients for sperm and fluid
What is the normal volume range for semen?
2-5 mL
What is the normal pH range for semen?
7.2-8.0
What is evaluated in sperm morphology?
Head, neck, midpiece, tail
What is the critical component of sperm for fertilization?
Sperm morphology
What is the purpose of semen analysis?
Investigation of fertility and identification of treatment options
What are the two main types of examinations performed in semen analysis?
- Macroscopic examination
- Microscopic examination
What is the significance of sperm motility in semen analysis?
Need to have sperm with forward, progressive movement
What is the normal percentage of motile sperm within 1 hour?
> 50%
What does a sperm count of >20 million/ml indicate?
Normal sperm concentration
What is the purpose of the eosin-nigrosin stain in sperm viability testing?
To differentiate living and dead sperm
What is the normal value for sperm viability?
75% living
What is a common method for semen collection?
Masturbation into a clean sample cup
What should be avoided when collecting a semen sample?
Lubricated, anti-spermicidal condoms
What is the normal liquefaction time for semen?
30 to 60 minutes
What should be recorded on the laboratory analysis form for semen analysis?
- Period of abstinence
- Sample collection completeness
- Time interval from collection to analysis
What is the normal sperm count per ejaculate?
> 40 million
What indicates a problem if the semen viscosity is too high?
Infertility, incomplete collection
What does ‘living’ correspond to in semen analysis?
Motility
Motility refers to the ability of sperm to move effectively.
What is the normal color of semen?
Gray-white/Pearly white
The color can indicate the health of the sperm.
What is the normal odor of semen?
Musty/bleach like
The odor can also provide insights into the quality of the semen.
What is the normal liquefaction time for semen?
30-60 minutes
Liquefaction is the process by which semen changes from a gel-like state to a liquid state.
What is the normal volume of semen?
2-5 ml
Volume is an important parameter in evaluating semen quality.
What is the normal viscosity of semen?
Pours in droplets
Viscosity affects sperm motility and overall fertility.
What is the normal pH range for semen?
7.2-8.0
The pH level can influence the survival of sperm in the female reproductive tract.
What is the normal sperm concentration in semen?
> 20 million/ml
Sperm concentration is crucial for assessing male fertility.
What is the normal sperm count per ejaculate?
> 40 million/ejaculate
Higher sperm counts are generally associated with better fertility potential.
What is the normal motility percentage of sperm within 1 hour?
> 50%
Motility is a key factor in determining the likelihood of successful fertilization.
What is the minimum quality rating for sperm?
> 2.0 or a, b, c
Quality ratings assess the overall health and viability of sperm.
What is the minimum percentage of normal forms for sperm morphology?
> 14% normal forms (strict criteria)
Morphology evaluates the shape and structure of sperm, which is important for fertility.
