Renal Function Test Flashcards
GLOMERULAR FILTRATION
measures the rate at which kidneys are able to REMOVE filtrable substances in blood
Clearance Test
GLOMERULAR FILTRATION
Clearance Test includes (4)
- Creatinine
- Cystatin C
- Radioisotopes
- B-2 microglobulin
GLOMERULAR FILTRATION
Clearance Test Specimen
24 hour Urine
GLOMERULAR FILTRATION
Greatest error of Clearance Test
Use of IMPROPERLY TIMED SPECIMEN
GLOMERULAR FILTRATION
First Voided urine @7am is included will cause
falsely ELEVATED
GLOMERULAR FILTRATION
Last Voided urine @7am is NOT included will cause
Falsely DECREASED
GLOMERULAR FILTRATION
single marker that denotes RENAL FAILURE
Creatinine
GLOMERULAR FILTRATION
marker for RENAL TUBULAR INTEGRITY
B2-microglobulin
GLOMERULAR FILTRATION
Polymer fructose
Inulin
GLOMERULAR FILTRATION
Extremely stable ; not a normal body constituent must be INJECTED THROUGH IV
Inulin
GLOMERULAR FILTRATION
Small protein (MW 13,359)
Filtered, reabsorbed, broken down by RTC
serum concentration is DIRECTLY RELATED TO GFR
Cystatin C
GLOMERULAR FILTRATION
MW 11,800
Dissociates from HLA
Rapidly removed from plasma by Glomerular Filtrate
INVERSELY RELATED TO GFR
B2-microglobulin
GLOMERULAR FILTRATION
Kidney disease has DECREASED GFR and ____ B2-Microglobulin
Increased
GLOMERULAR FILTRATION
Injecting radionucleotides (125I-iothalamate)
Disappearance of radioactive material in plasma
measure VIABILITY OF KIDNEY TRANSPLANT
Radioisotopes
GLOMERULAR FILTRATION
Waste product of muscle metabolism
Creatinine
GLOMERULAR FILTRATION
Endogenous substance
Creatinine
Normal Creatinine:
120 mL/min
GLOMERULAR FILTRATION:
Estimated GFR (eGFR) (2)
- Cockroft-Gault
- Modification of Diet in Renal Disease (MDRD)
GLOMERULAR FILTRATION:
Results are NOT CORRECTED for body surface area ; woman have 15% lower creatinine clearance
Cockcroft-Gault
GLOMERULAR FILTRATION:
Cockcroft-Gault includes factors:
BAGS
- Body Weight
- Age
- Gender
- Serum Creatinine
GLOMERULAR FILTRATION:
Provided more accurate assessment in GFR; does not require patient’s weight
MDRD
GLOMERULAR FILTRATION:
MDRD includes factors:
RAGS:
- Race
- Age
- Gender
- Serum Creatinine
GLOMERULAR FILTRATION:
MDRD also includes factors:
- Serum albumin
- BUN
- Race
First Function to be affected in RENAL DISEASE
Tubular Reabsorption
Tubular Reabsorption uses CONCENTRATION TESTS such as (2)
- Specific Gravity
- Osmometry
TUBULAR REABSORPTION:
most useful screening procedure and quantitative of renal concentrating ability
Specific Gravity
TUBULAR REABSORPTION:
patients were deprived of fluids for 24 hours before measuring SG (SG 10.26 or higher)
Fishberg Test
TUBULAR REABSORPTION:
compared volume and specific gravity of day and night
Mosenthal Test
TUBULAR REABSORPTION:
- Quantitative measurement of CONCENTRATING ABILITY
- Measures only the number of PARTICLES in solution
Osmometry
TUBULAR REABSORPTION:
Performed for more accurate evaluation of renal concentrating ability
Osmolality
TUBULAR REABSORPTION:
Measurement of freezing point depression
Freezing point osmeter
TUBULAR REABSORPTION:
1 mol of non-ionizing substance dissoved in1 kg of water is known to LOWER freezing point
- 1.86 deg celsius
Measure tubular secretion of nonfiltered substances; measured by a substance THAT IS SECRETED
Tubular Secretion and Renal Blood Flow
TUBULAR SECRETION:
Tests (2)
- Phenolsulfonpththalein (PSP) dye
- P-aminohippuric Acid Test (PAH Test)
Titratable Acidity and Urinary Ammonia
Tubular Secretion
Normal person excretes approximately _____ of titratable acids
70 mEq/day
Inability to produce Acidic urine
Metabolic acidosis
Renal Tubular Acidosis
- Impaired secretion of hydrogen ions in PROXIMAL convulated tube
- Defects in Ammonia secretion with DISTAL convulated
Renal Tubular Acidosis
