Term
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Definition
| The most common test for assessing renal function |
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Term
| Basic Urinalysis assesses (5) |
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Definition
pH – Acidity/Alkalinity
Specific gravity (concentrating ability)
Protein Concentration – Initial indicator of disease
Nitrite Concentration – Bacterial Infection
Blood |
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Term
| 6 things to evaluate when a significant disease is suspected |
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Definition
Renal Blood flow
Glomerular filtration rates
Clearance capabilities
Tubular reabsorption capabilities
Tubular secretion capabilities |
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Term
| Glomerular Filtration Tests |
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Definition
| The standard test for measuring filtering capacity of the kidney is the clearance test. |
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Term
| Clearance tests measure the rate of what? |
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Definition
| rate at which the kidneys are capable of removing a filterable substance from the blood |
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Term
| Important factors in clearance tests (5) |
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Definition
Substance must neither be reabsorbed or secreted by the kidney tubules
Substance must be stable during the collection period ( usually 24 hrs)
Consistency of the plasma level
Substance’s availability to the body
Test availability |
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Term
| The clearance of a substance (definition) |
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Definition
| volume of plasma from which that substance is completely cleared by the kidney per unit of time |
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Term
| Does every substance in the blood have a unique clearance rate? |
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Definition
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Term
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Definition
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Term
| Why is Inulin used for clearance tests? |
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Definition
| Not a normal body substance requires constant infusion throughout the test period (exogenous procedure) |
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Term
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Definition
| Polymer of fructose that is extremely stable and not reabsorbed or secreted by the tubules |
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Term
| Why is inulin clearance test not used often |
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Definition
| suitable endogenous procedure is available |
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Term
| Creatinine Clearance Test. |
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Definition
| This test evaluates how efficiently the kidneys clear a substance called creatinine from the blood. |
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Term
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Definition
| a waste product of muscle energy metabolism, is produced at a constant rate that is proportional to the muscle mass of the individual |
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Term
| Why is craetinine clearance specific for kidney function? |
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Definition
| Because the body does not recycle it, all of the creatinine filtered by the kidneys in a given amount of time is excreted in the urine |
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Term
| Why kind of urine sample is the creatinine clearance test performed on? |
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Definition
| timed urine specimen--a cumulative sample collected over a two to twenty-four hour period. Determination of the blood creatinine level is also required to calculate the urine clearance. |
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Term
| Disadvantages to Creatinine test (5) |
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Definition
Some creatinine is secreted by the tubules and secretion increases as blood levels rise
Chromogens in blood plasma react with the chemical analysis
Creatinine breakdown by bacteria if specimens are kept at room temperature
Heavy meat diet during collection period may influence results if plasma levles are drawn prior to the urine collection period
Inaccurate in patients with muscle wasting diseases |
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Term
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Definition
| waste product that is created by protein metabolism and excreted in the urine. |
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Term
| requirements of the urea clearance test? |
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Definition
| The urea clearance test requires a blood sample to measure the amount of urea in the bloodstream and two urine specimens, collected one hour apart, to determine the amount of urea that is filtered, or cleared, by the kidneys into the urine. |
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Term
| Clearance Tests Calculations, Standard formula |
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Definition
C= UV/PT
C = ml. plasma cleared per minute
U = urine concentration
P= Plasma concentration
V= Volume
T = collection period (mins) |
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Term
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Definition
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Term
| Corrected Clearance formula |
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Definition
| C = UV/PT X 1.73 Square Meters/Patient Surface Area |
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Term
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Definition
| functional capacity of the nephrons not by the number of functioning nephrons |
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Term
| Is creatinine clearance a good detection for early renal disease? |
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Definition
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Term
| uses of the creatinine clearance test? (3) |
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Definition
Determine extent of nephron damage in known renal disease
Monitor effectiveness of treatment in preventing further nephron damage
Feasibility of administering medications that may be toxic in cases of reduced GFR |
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Term
| First functional change in renal disease |
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Definition
| Loss of tubular reabsorption capabilities |
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Term
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Definition
| address the reabsorption of salts and water |
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Term
| urine concentration is largely determined by |
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Definition
| body’s hydrational status. |
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Term
| Patients with normal concentrating abilities should have a specific gravity of _____ when deprived of fluids for 16 hours |
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Definition
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Term
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Definition
| – depends on the number of particles present in solution |
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Term
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Definition
| Good correlation between the GFR and the plasma levels of beta2 microglobulin has been demonstrated. |
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Term
| What is Beta2 microglobulin |
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Definition
| Molecule dissociates from the human leukocyte antigens at a constant rate and is rapidly cleared from the plasma. |
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Term
| Increased levels of beta2 microglobulin has been shown to be a more sensitive indicator of |
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Definition
| decreased GFR than the creatinine clearance |
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Term
| When is the beta2 microglobulin not reliable? |
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Definition
| Test is not reliable in patients with malignancy or immunological disorders |
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Term
| Clinical Significance of Tubular Reabsorption Tests |
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Definition
Evaluates renal concentrating abilities
Monitoring the course of renal disease
Monitoring fluid and electrolyte therapies
Differential diagnosis of hypernatremia and hyponatremia and polyuria
Evaluating secretion of and renal response to ADH |
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Term
| Tubular Secretion and Renal Blood Flow |
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Definition
| Tests to measure tubular secretion of nonfiltered substances and renal blood flow are closely related in as much as total renal blood flow through the nephron must be measured by a substance that is secreted rather than filtered through the glomerulus. |
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Term
| Abnomalities in Tubular Secretion and Renal Blood Flow tests |
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Definition
| related to either impaired secretion or inadequate presentation of the substance to the capillaries |
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Term
| most common Tubular Secretion and Renal Blood Flow tests |
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Definition
PAH – para aminohippuric acid test
PSP – phenolsulfonphthalein test |
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Term
| Para Amino Hippurate Test principle |
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Definition
| Principles are the same as the clearance test however the substance must be removed from the plasma in the peritubular capillaries rather than at the glomerulus |
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Term
| Why does PAH fulfill the criteria for a clearance test? |
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Definition
| It is a high MW substance that binds loosely to plasma proteins and is completely removed in the peritubular capillaries. |
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Term
| How to ensure accurate PAH results? |
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Definition
| The quantity of PAH infused must be monitored |
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Term
| PAH clearance is a method used to measure |
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Definition
| renal plasma flow, which, in turn, is a measure of renal function. |
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Term
| Renal Perfusion flow calculation |
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Definition
RPF = U(pah)/P(pah) x v
P(pah)= PAH in aterial blood
U(pah) = PAH in urine
V = urine flow |
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Term
| eRPF almost equals RPF because |
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Definition
| the renal extraction ratio of PAH almost equals 1 |
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Term
| The renal extraction ratio of PAH in a normal individual is |
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Definition
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Term
| What do you need to take into account when measures RPF with PAH? |
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Definition
| , this method usually underestimates RPF by approximately 10%. |
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Term
| Why is it okay for the PAH test to be inaccurate? |
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Definition
| considering the ease with which eRPF is measured |
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