Exam 1 Flashcards
What is the purpose of the QA program in the lab?
To ensure the quality of a laboratory’s test results
What 3 aspects comprise the QA program? Give an example of each.
- pre-analytical ex. sample collection
- analytical ex. instrument maintenance
- post-analytical ex. critical values
Universal Precautions (UP)
Established in response to HIV/AIDS
Blood/Body fluid precautions
Exempted urine, feces, sputum and vomit from precautions unless blood present
Recommended handwashing after glove removal
Initiated by the CDC
Body Substance Isolation (BSI)
Emphasized avoidance of bodily fluid contact regardless of presence or absence of blood
Only recommended handwashing if hands are visibly soiled
Initiated by CDC
Bloodborne Pathogens Standard (BPS)
Main goal to reduce healthcare worker exposure to bloodborne pathogens when caring for patients with known infection
Requires Exposure Control Plan
Initiated by OSHA
Standard Precautions and Transmission Based Precautions
Emphasized prevention of nosocomial infection
Standard precautions refers to ALL body fluid/tissue specimens
Prevent airborne/droplet/contact transmission
Enacted by HICPAC/CDC
T/F: Urine can be discarded down the sink
True
How to properly dispose of urine?
Urine can be dumped down the sink, but the sink must be rinsed after disposal and should be cleaned daily with 0.5% bleach solution
What 5 elements must be included on OSHA chemical labels?
- product name
- signal word (danger)
- hazard statement
- Precautionary statement/pictogram
- supplier identification
What do the colors and numbers on the NFPA hazard identification system indicate?
Blue - health hazard Red - fire hazard Yellow - reactivity hazard White - specific hazard The higher the number, the worse the hazard
2 very important chemical safety tips
- never grasp a reagent bottle by the neck or top
2. ALWAYS add acid to water. NEVER add water to acid
Random Urine Specimen - what is it? pros and cons?
Collected at any time without prior patient prep.
Pros - easy, good for routine screening
Cons - excessive fluid intake/exercise can affect composition of urine and cause inaccurate reflection of patient health
Timed Collection Specimens - what is it? Pros and cons?
Urine collected for a determined amount of time (12 or 24 hour or specific time of day)
Pros: very accurate patient results if rules followed
Cons: must follow strict rules for accurate results
Rules for Timed Collection specimens
Never include first two morning specimens in your collections
Must void all urine before timed specimen begins
Must collect every other void of urine after that during the time frame
Must have adequate volume
First Morning specimen - what is it? Pros and Cons?
Patient voids before going to bed and then collects the specimen first thing in the morning after sleeping
Pros - ideal for substances that require concentrated urine, formed elements are more stable
Cons - high salts can crystalize, not the most convenient
Technique for midstream clean-catch? When would this technique be used?
- clean genitals with wipe - DO NOT touch the inside of the cup
- void first stream of urine into toilet
- midportion of stream goes into collection cup
- remaining urine goes into toilet
This is used for bacterial/fungal cultures.
Collection technique for a catheterized specimen? When is this used?
Requires medical personnel - Insertion of sterile catheter through urethra into the bladder, urine flows from bladder into catheter and into a bag
Used for bacterial cultures
Collection technique for suprapubic aspiration? When is it used?
Requires medical personnel - urine collected by puncturing abdominal wall and distended bladder using a needle and syringe
Used for bacterial culture, specifically anaerobic organisms
Collection techniques for pediatric collections? When is it used?
This is used for patients who cannot voluntarily urinate
Plastic urine collection bags with skin adhesive are put onto genitals.
Used for routine screening
Reasons for urinalysis specimen rejection
Unlabeled/Mislabeled Incorrect/no preservation Insufficient Volume Contamination Inappropriate collection technique used
How much volume is required for routine urinalysis?
10-15 mL
How much volume is required for 24-hour-collection specimens?
only 1 mL of well mixed urine despite the large collection volume
Valid 24hr urine collection containers - what must they look like
Must have a capacity of 3000 mL
Must be wide-mouth
Must be brown, opaque, plastic to protect from light
Valid urine collection bag
Clear, polyethylene
Can be sterile or nonsterile
Self-sealing
What are the potential changes in color, clarity, or odor of unpreserved urine?
Color - darkens
Clarity - decreases
Odor - becomes foul/ammonia-like
What are the potential microscopic changes of unpreserved urine?
blood cells - decrease
casts - decrease
bacteria - increase
trichomonads - decrease
What are the potential chemical changes of unpreserved urine? (glucose, pH, ketones, bilirubin, urobilinogen, nitrite)
pH increases
Nitrite increases
Glucose, bilirubin, urobilinogen, and ketones all will decrease
Thymol - uses, advantages, disadvantages
Urine preservative used for sediment preservation
Adv - preserves casts and cells while inhibiting bacteria and yeast
Disadv - can precipitate crystals
Formalin - uses, advantages, disadvantages
Used for cytology
Adv - great preservative
Disadv - false-negative reagent strip tests for blood and urobilinogen
HCl, acetic acid - uses, adv, disadv
Quantitative analysis of urine solutes like steroids/hormones
Adv - inexpensive, stabilizes elements and solutes
Disadv - unacceptable for urinalysis testing and chemical hazard
What is the easiest and most common form of preservation used in urinalysis?
Refrigeration at 4-6 degrees C
Refrigeration as preservative - uses, advantages, disadvantages
Used for storage before/after majority of specimens
SPECIMEN MUST BE BROUGHT BACK TO ROOM TEMP BEFORE TESTING
Adv - acceptable for routine urinalysis for 24 hours, inhibits bacterial growth up to 24 hours
Disadv - can precipitate solutes and crystals such as amorphous urate and phosphate crystals for microscopic exams
How do you determine if a fluid is urine as opposed to some other fluid?
Specific Gravity - must be 1.002-1.035
pH - must be 4.0-8.0
Temp - between 32 and 37 deg C
High creatinine concentration
Cortex of the kidney
Outer granular layer of the kidney, site of plasma filtration
Medulla of the kidney
Inner layer composed of renal tissue shaped into pyramids, contain papilla
minor/major calyces
act as a funnel to receive urine from collecting ducts and pass it to renal pelvis
Flow of urine from nephrons to urethra
Nephron -> Minor calyces -> Major calyces -> Renal pelvis -> ureters -> bladder -> urethra
What is the functional unit of the kidney?
Nephrons
5 parts of the nephron and in order of flow
Glomerulus -> PCT -> Loop of Henle -> DCT -> Collecting Duct
What percent of cardiac output do kidneys receive?
25% of cardiac output
Purpose of the renal artery
Delivers blood from the heart to the kidney
Purpose of the afferent arteriole
supplies blood to the glomerulus of each nephron
Purpose of the efferent arteriole
allows blood to leave the glomerulus
Purpose of the vasa recta in the nephron
U shaped vessels that descend into the renal medulla to supply blood to the nephron
What forces are involved in glomerular filtration? Are they positive or negative?
Hydrostatic force from blood pressure - positive
Hydrostatic force from ultrafiltrate already present - negative
Oncotic force from protein in blood - negative
Is the net pressure in glomerular filtration positive or negative?
Positive
Hydrostatic pressure vs oncotic pressure
Hydrostatic pressure is force exerted by proteins in blood vessels that pushes fluid into capillaries
Oncotic pressure is force exerted by fluid inside the capillaries that pushes fluid out of capillaries
What would happen if oncotic pressure was increased?
Net pressure would be negative and glomerular filtration would be unfavored, reabsorption would occur
What would happen if hydrostatic pressure were increased?
Net pressure would be increased more positively and glomerular filtration would be increased
What would occur if hydrostatic and oncotic pressure were equal?
No net movement would occur
mmHg must be positive for what to occur?
mmHg must be negative for what to occur?
+ mmHg supports filtration
- mmHg supports reabsorption
What is the principle producer of renin in the kidney?
Juxtaglomerular apparatus
What does renin stimulate the formation of? What does this product then secrete?
Renin stimulates the formation of angiotensin which then causes the secretion of aldosterone
What 3 processes are involved in urine formation? What aspect of the nephron is responsible for each process?
- Filtration - glomerulus
- Reabsorption - Renal tubules
- Secretion - Renal tubules
What is the normal daily urine volume excreted?
600-1800 mL
The kidneys filter ______ of plasma each day.
180,000 mL or 125 mL/min
What analytes should NOT normally be found in urine?
glucose, bicarbonate, albumin, protein
Urine is comprised mostly what?
Water
What is the first component of the glomerulus filtration barrier?
Capillary endothelial cells (fenestrated)
What is the second component of the glomerular filtration barrier?
Basement membrane
What is the third component of the glomerular filtration barrier?
Podocytes
Tubular reabsorption
substances moved from tubular lumen into capillary blood (coming back into the body, not excreted in urine)
Tubular secretion
Substances moved from capillary blood into tubular lumen (will exit in urine)
Which part of the nephron does not secrete H2O?
The ascending limb is not permeable to H2O.
Where are glucose, amino acids, proteins, phosphate, sulfate, magnesium, and calcium reabsorbed in the nephron?
In the PCT
Roles of the reabsorptive process
reabsorb substances necessary for the maintenance of body homeostasis and function
Roles of the secretory process
eliminate metabolic wastes and adjust the acid-base equilibrium of the body
Substances that are secreted by the nephron
Urea, uric acid, ammonia, hydrogen ions
What do the kidneys excrete is there is excess alkali?
sodium salts
What do the kidneys secrete if there is excess acids?
titratable acids and ammonium salts
What is normal blood ph?
7.35-7.45
What are the 3 secretory mechanisms of the kidney to maintain blood ph?
H+ ion secretion to recover bicarbonate
H+ ion secretion to yield urine titratable acids
H+ ion and NH3 secretion to yield ammonium salts
** Hydrogen ion secretion results in sodium/bicarbonate reabsorption **
