1. CM - GFC Flashcards
The primary blood vessel that carries oxygenated blood from the abdominal aorta to the kidneys:
RENAL ARTERY
The kidneys maintain a concentration gradient of solutes in the renal medulla to facilitate the concentration of urine. This is primarily due to the ______ Multiplier system involving the loop of Henle and the vasa recta.
COUNTER CURRENT MECHANISM
The highest solute concentration in the kidney is found in the inner region of the renal medulla, particularly around the_____ and ___ where the kidney creates a high osmolarity environment necessary for water reabsorption and urine concentration.
Loop of Henle and CD
Tuft of 8 capillaries within the Bowman’s capsule that resembles a sieve:
Glomerulus
Basic structural and functional unit of the kidney:
Nephron
Nonselective filter of plasma substances of MW of Daltons?
<70.000 Daltons MW
Major site of reabsorption of plasma substances:
Reabsorbing approximately 65% of the filtered substances such as salts (sodium, chloride, bicarbonate), water, glucose, amino acids, and urea
PCT
Permeable to water but impermeable to solutes:
DLOH (no solute reabsorption)
Impermeable to water but actively reabsorbs solutes:
ALOH (no water reabsorption)
Regulates water reabsorption in the DCT and CD:
**High: Increases water permeability in the DCT and CD, leading to increased water reabsorption and concentrated urine = LOW URINE VOL
** Low: Decreases water permeability in the DCT and CD, leading to decreased water reabsorption and dilute urine= HIGH URINE VOL
ADH/VASOPRESSIN
Regulates sodium reabsorption:
ALDOSTERONE
produced by ADRENAL CORTEX
A condition where the kidneys are unable to excrete hydrogen ions (H*) effectively, leading to an inability to produce acidic urine:
REAL AULAR ACIDOSIS
**Urine pH: Alkaline
** Blood pH: Acidic
Renal threshold for glucose:
100-180 mg/dl
Renal threshold for sodium:
120 mmol/L
Renal threshold for water and potassium:
No renal threshold
Renal threshold for magnesium:
1.46-2.07 mg/dL (0.60-0.85 mmol/L)
Renal threshold for ketones:
70 mg/dl
Normal Renal blood flow:
1200 ml/min
Renal plasma flow:
600-700 ml/min
Major components of urine?
WATER
Major component of urine, acting as a solvent for the waste products and electrolytes:
WATER
Major organic substance in urine
UREA
Major electrolyte and principal salt in urine:
SODIUM
Major inorganic substance in urine:
Cl > Na > K
Glomerular Filtration Rate Assessment Markers (ClearanceTest)
(most common)?
Creatinine
Glomerular Filtration Rate Assessment Markers (ClearanceTest)
(gold standard/reference)-
Inulin
** others:
-B2-microglobulin
-Cystatin
-Radioisotopes such as 99mTc-DTPA or 1251-iothalamate
Glomerular Filtration Rate Assessment Markers (ClearanceTest)
(old method)?
Urea
Creatinine ClearanceTest Formula:
CCUV/P x 1.73m²/A
✔U-Urine creatinine (mg/dL)
✔V-Urine volume (mL/min)
✔P-Plasma creatinine
✔A-Body surface area
Normal GFR:
120 ml/minute
he greatest source of error in Clearance tests:
Improperly timed urine specimens
Under-collection of urine causes what?
Falsely Low clearance rate
Over-collection of urine causes what?
Falsely High clearance rate
Analytes to definitively identify an unknown body fluid as urine:
Urea and creatinine
Tubular Reabsorption (Concentration Test)
- (Influenced by the number and density of particles)
Specific gravity
Tubular Reabsorption (Concentration Test)
(influenced by the number of particles)
Osmolality
Tubular Reabsorption (OBSOLETE Concentration Test)
(24 hours fluid deprivation, SG is measured 21.026) *12 hours ≥1.022
FISHBERG TEST
Tubular Reabsorption (OBSOLETE Concentration Test)
(compare the SG and volume of day and night urine)
MOSENTHAL TEST
Tubular Secretion and Renal Blood Flow:
✔p-aminohippuric acid (PAH) test
✔Phenolsulfonphthalein (PSP) test (obsolete, hard to interpret)
The purpose of the second container in the three-glass technique is to serve as a ____for UTI, specifically for detecting cystitis.
Control
Urine specimens should be tested within ____ collection to ensure accurate results. If testing is delayed, ____ is the most commonly used method of urine preservation and the specimen should be allowed to return to ____ before testing.
2 hours ; refrigeration ; RT
RBCs, WBCs, and casts can disintegrate or break down in what urine?
alkaline hypotonic urine
remains relatively stable in unpreserved urine because it is not as easily degraded or broken down by environmental conditions like bacteria or pH changes.
PROTEIN/ ALBUMIN
An effective preservative because it inhibits bacterial growth and the degradation of protein (including albumin) in urine:
THYMOL BORIC ACID
If a urine specimen is unlabeled, it should be
REJECTED
Urine culture should always be performed first to allow for optimal bacterial growth. Afterward, a urinalysis can be performed to examine the macroscopic and microscopic. properties of the urine. If a urine specimen is submitted for urinalysis before being sent for culture, it should typically be ___
REJECTED
if a urine specimen is not processed immediately for culture, ____ is strongly recommended to preserve the integrity of the sample.
REFRIGERATION
The major pigment responsible for the yellow color of urine.
✓Source: It is produced during the breakdown of hemoglobin in RBCs, specifically from the degradation of bilirubin.
*UROCHROME
A pink pigment in urine.
✔Source: It is found as a product of the breakdown of urates, specifically amorphous urates and uric acid crystals.
UROERYTHRIN
____in the urine lower the surface tension of the liquid, which causes the formation of white foam or bubbles.
PROTEIN / ALBUMIN
A dark yellow/orange pigment in urine.
✓Source: It is a product of bilirubin degradation during the breakdown of RBCs.
UROBILIN
Yellow foam from urine can be caused by _____ (in cases of liver disease or bile duct obstruction) or ____ (a medication for UTIs).
BILIRUBIN ; PYRIDIUM
Phenol in urine typically produces a ____ or____ color due to oxidation. This can occur from exposure to phenolic compounds in certain medications, like acetaminophen, or environmental sources.
GREENISH BROWN ; BROWN
______: Causes bright yellow or fluorescent yellow urine
B Complex Vitamins (B2/Riboflavin)
Can cause dark yellow to orange urine, typically associated with the intake of foods rich in this or supplements.
Carotene (Beta-Carotene)
What is the most common abnormal urine color?
red
Clear red urine due to intravascular hemolysis:
Hemoglobinuria
Clear red or reddish-brown urine due to muscle damage (rhabdomyolysis):
Myoglobinuria
Cloudy or smoky red urine due to the presence of intact RBCs:
Hematuria
Tea-colored urine can be caused by the presence of
BILIRUBIN or MYOGLOBIN
Port wine or burgundy/purplish-red urine is often caused by
PORPHYRIA
The following substances can cause BLACK or BROWN urine
(from alkaptonuria)?
Homogentisic acid
The following substances can cause BLACK or BROWN urine
(from hemolysis or chemical exposure)?
Methemoglobin
The following substances can cause BLACK or BROWN urine
(from melanoma)?
Melanin
The following substances can cause BLACK or BROWN urine
(from toxins or medications)?
Phenol
The following substances can cause BLACK or BROWN urine
(medication for hypertension)?
Methyldopa
The following substances can cause BLACK or BROWN urine
(silver-based medication)?
Argyrol
The following substances can cause BLACK or BROWN urine
(antibiotic)?
Metronidazole
A large number of coliforms in urine, such as E. coli, can cause a ____ odor? and nitrite-positive urine
foul or ammoniacal odor
Important in the identification of crystals and identification of unsatisfactory specimens:
pH
Normal random urine pH
4.5-8.0 pH
1st morning urine pH
5.0-6.0 pH
Unpreserved urine pH:
9.0 pH
fruit commonly associated with causing acidic urine and are often used as a home remedy for UTI or bladder infections.
CRANBERRIES
CRANBERRIES contain compounds like _____ that may help prevent bacteria from adhering to the bladder wall, reducing the risk of infection.
proanthocyanidins
A vegetable-based diet typically results in _____ urine. Vegetables, particularly fruits, leafy greens, and root vegetables, are rich in ___ and ___, which can help neutralize the acid in the body.
Alkaline;
potassium and magnesium
Normal urine protein concentration:
<150 mg/day
Protein RST indicator is sensitive to:
Albumin
A positive SSA test with a negative protein dipstick or RST result indicates presence of ____
NON-ALBUMIN PROTEIN.
SSA negative, Protein positive =
False positive RST (Highly buffered Alkaline urine)
The primary protein seen in the urine seen in patients Multiple Myeloma:
BENCE-JONES PROTEIN
BJP- Coagulating at temperatures between____ and dissolving at ____
40-60°C and 100°C
Increased renal vein pressure in the upright position is believed to cause _____ with protein leakage into urine occurring when standing (upright), but not when lying down (supine).
ORTHOSTATIC PROTEINURIA
For detecting orthostatic proteinuria, the patient should:
EMPTY THE BLADDER BEFORE BED
*Collect a morning urine sample after waking up, before standing
*Collect another sample after standing
A nonspecific test for reducing sugars, detecting various sugars by causing a color change through copper ion reduction:
Clinitest & Benedict’s test
Causes of false POSITIVES in the copper reduction test include:
VITAMIN C
URIC ACID
levodopa
bilirubin
acetaminophen
tetracycline
Formalin
Causes of false NEGATIVES in the copper reduction test include _____ the _____ phenomenon due to high glucose concentrations, improper sample handling, and excessive dilution.
DETERGENTS ; PASS THROUGH
To prevent the pass-through phenomenon in the copper reduction test, it is recommended to use_____of urine. This helps ensure the test detects even low concentrations of sugars without overwhelming the reaction.
2 mg/dl
Rubner’s test detects ____ sugar (Brick red with yellow precipitate) and ___ sugar (Brick red with red precipitate)
LACTOSE ; GLUCOSE
If the glucose reagent strip test shows 4+ (high glucose levels), it is important to check other parameters, such as ____ and ____
ketones and protein
What by-products are produced due to increased fat metabolism in patients on a starvation diet or with carbohydrate metabolism defects, and can be excreted in the urine?
KETONES
What is the major ketone found in urine that is not detected by the reagent strip test?
B-hydroxybutyric acid (78%)
What is the parent ketone found in urine, and what percentage does it represent?
Acetoacetic acid (20%)
What is the minor ketone found in urine?
Acetone (2%)
What substances are commonly found in urine after crush injuries?
MYOGLOBIN, HEMOGLOBIN
These substances are toxic to the renal tubular epithelium and can cause direct damage to the renal tubules, leading to acute tubular necrosis (ATN).
MYOGLOBIN, HEMOGLOBIN
What drug can cause rhabdomyolysis, leading to myoglobinuria?
STATINS (e.g., atorvastatin, simvastatin, rosuvastatin)
✓Other drugs, such as cocaine, alcohol, and certain antipsychotics, can also contribute to this condition.
Test used to differentiate between hemoglobin and myoglobin in urine:
BLONDHEIM’S TEST (AMMONIUM SULFATE TEST)
BLONDHEIM’S TEST (AMMONIUM SULFATE TEST)
When combined with ammonium sulfate, it forms a red precipitate.
Hemoglobin
BLONDHEIM’S TEST (AMMONIUM SULFATE TEST)
When combined with ammonium sulfate, it does not precipitate, leaving a red supernatant.
Myoglobin:
How should a urine specimen be handled for a bilirubin test?
The urine specimen should be _____ to protect it from light, as light can degrade bilirubin, leading to inaccurate results.
WRAPPED IN FOIL
What is an early indication of liver disease, significant for screening diseases like Hepatitis, Cirrhosis, and Biliary duct obstruction?
Bilirubin
What is a more sensitive and less interference-prone test for the determination of bilirubin?
- A positive result is indicated by a ____ color after 60 seconds
ICTOTEST ; blue to purple
What bile pigment results from hemoglobin degradation and is typically found in urine?
UROBILINOGEN
It is the only analyte that is not reported as negative. The specimen for testing is usually PM urine (2-4 pm peak), and the usual amount is <1 mg/dL or Ehrlich unit.
UROBILINOGEN
How can urobilinogen, porphobilinogen, and other Ehrlich-reactive substances be differentiated in urine?
WATSON SCHWARTZ TEST
WATSON SCHWARTZ TEST
chloroform = SOLUBLE
butanol = SOLUBLE
Urobilinogen
WATSON SCHWARTZ TEST
chloroform = INSOLUBLE
butanol = INSOLUBLE
Porphobilinogen
WATSON SCHWARTZ TEST
chloroform = INSOLUBLE
butanol = SOLUBLE.
Other Ehrlich-reactive substances:
Indican
Methyldopa
Procaine
Sulfonamide
What is the rapid screening test for porphobilinogen?
Hoesch test (Inverse Ehrlich Reaction)
What is the rapid screening test for UTI and bacteriuria?
Nitrite test
Nitrite test
The specimen typically being ____ or ____.
_____ bacteria such as Escherichia coli (E. coli), Klebsiella, Enterobacter, and Proteus typically produce a positive nitrite test, as they reduce nitrate to nitrite in the urine.
first morning or 4-hour urine ;
Gram-negative
Nitrite test
To prepare for the test, it is recommended to ______ the night before, they can increase the levels of nitrite in the urine, potentially aiding in the detection of UTI.
EAT VEGETABLES
NITRITE TEST
The principle of the nitrite test is based on a _____ color reaction. The azo dye in the test reacts with aromatic compounds, specifically nitrites present in the urine, resulting in a color change that indicates a positive result.
Greiss = pink color
What test is good for determining UTI and inflammation, and for screening urine culture specimens?
Leukocyte test
Leukocyte test
The principle of the Leukocyte esterase test is that all leukocytes, except for _______ contain leukocyte esterase, which reacts with the reagent on the test strip produce a color change, indicating the presence of leukocytes in the urine.
LYMPHOCYTES
Urine specific gravity of <1.010, indicatin diluted urine.
Hyposthenuria
Urine specific gravity of 1.010, indicating concentration similar to plasma.
- Renal tubular failure
Isosthenuria
Urine specific gravity of >1.010, indicating concentrated urine.
Hypersthenuria
How do you calculate the actual SG of a urine specimen the SG reading after a dilution is 1.020 and the dilution factor is 1:8?
To calculate the actual SG, multiply the decimal portiion the SG reading by the dilution factor:
0.020 × 8 = 0.160
1 + 0.160 = 1.160
Correction for glucose and protein:
For every 1 g/dL glucose: _____ from the SC reading
For every 1 g/dL protein: ______ from the SG
glucose = Subtract 0.004
protein = Subtract 0.003
What is the relationship between urine SG and urine volume?
INVERSELY PROPORTION
Key factors to consider when performing Urinometry (hydrometer)
✔Required urine volume:
✔Temperature correction:
✔For every 3°C above:
✔For every 3°C below:
✔Required urine volume: 10-15 mL
✔Temperature correction: (calibrated at 20°C)
✔For every 3°C above: Add 0.001 to the SG reading
✔For every 3°C below: Subtract 0.001 from the SG reading
