Nonprotein Nitrogen & Renal Function, Analysis, and Disease

Name 4 Protein-Free Nitrogen-Containing Compounds in Plasma
Ammonia
Urea
Creatinine
Uric Acid
Ammonia is derived from protein breakdown in what 2 organs?
Intestines
Muscle
AA taken up by the liver, produce ammonia, then converted into what?
Urea
Where is Urea excreted?
Urine
Neurotoxic =
Encephalopathy
Are Decreased levels of Ammonia Significant or Insignificant?
Insignificant
What are the 3 disease correlations with Ammonia
Hepatic failure
Reye’s Syndrome
Poor Circulation
What is Reye’s Syndrome usually preceded by?
Viral infection + aspirin
Reye’s Syndrome – Fatty infiltration of what organ?
Liver
What type of tube should you use when collecting for Ammonia?
Heparin or EDTA
After placing the tube in Heparin or EDTA what should you do?
Put on ice Immediately
After putting your ammonia sample on ice what do you do?
Centrifuge at 0-4 Degrees Celsius and assay ASAP
Freeze
Which Nonprotein Nitrogen is affected by cigarette smoking?
Ammonia
Enzymatic reaction of Ammonia measure the amount of what consumed?
NADP
Name 2 interfering factors for Ammonia lab analysis
Glassware detergents
Impure water
What is the reference range for Ammonia?
11-35 micromoles/Liter
If the ammonia value is greater than what it is considered a panic value?
35 micromoles/Liter
What does BUN stand for?
Blood Urea Nitrogen
Where is Urea synthesized?
Liver from NH3
Almost half of all NPN is found where?
Plasma
What is the major waste product of protein metabolism?
Urea
Urea is filtered by which organ?
Kidneys
Decreased BUN is seen in what 3 conditions?
Low protein diets
Starvation
Liver Disease
What should the BUN/Cr ratio be?
10:1 – 20:1
>20:1 is associated with Pre-renal or Renal?
Pre-Renal
<10:1 is associated with Pre-renal or Renal?
Renal
What word is given to describe High levels of BUN in the blood?
Azotemia
What can cause Pre-renal diseases in association with Urea?
Reduced blood flow to kidneys
High Protein Diets
Increased breakdown of proteins
What can cause Renal diseases in association with Urea?
Any renal condition that reduces GFR
Uremia
Uremic Syndrome
What can cause Post-renal diseases in association with Urea?
Obstruction of urine flow
Uremia
High Levels of BUN with Renal Failure
True or False:
Uremic Syndrome is fatal if untreated by dialysis or transplant
True
What type of reactions do you perform in the lab when analyzing urea?
Coupled reaction using urease enzyme
What 2 substances inhibit urease?
Fluoride
Citrate
What is the reference range for Urea?
6-20 mg/dL
What 2 collection tubes should be avoided when analyzing urea?
Gray & Blue
Creatine is used in production of what?
Energy in muscles
What is the end-product of Creatine producing energy in muscle?
Creatinine
What is the major waste product of muscle metabolism?
Creatinine
True or False:
Creatinine is excreted at a constant rate daily
True
True or False:
Creatinine is proportional to a person’s muscle mass
True
What non-protein nitrogen-containing substance is NOT affected by exercise?
Creatinine
What is Creatinine filtered by?
Glomerulus
What is the main disease that correlates with Creatinine?
Renal dysfunction affecting filtration
Creatine Clearance Test Formula:
((Urine cr)/(Serum cr))/ ((Urine Volume)/Urine Collection Time))
How do you correct Creatine Clearance for body surface area?
CrCl x (1.73/BSA)
Renal Damage = Decrease in what?
CrCl & GFR
Renal Damage = Increase in what?
Serum Cr/BUN
Are Decreased Levels of Creatine Significant or Not Significant?
Not Significant
True or False:
50% of renal function may be lost before CrCl is Decreased
What is the classic method of Creatine lab analysis based on?
Jaffee reaction
What can cause a false negative in Creatine lab analysis?
Bilirubin
Hemoglobin
What 4 substances can cause a false positive in Creatine lab analysis?
Cephalosporins
Uric Acid
Ascorbic acid
Glucose
What is the reference range for Creatinine?
0.6-1.0 mg/dL (m/f average)
Uric acid is the breakdown product of what?
Purines from nucleic acids
What type of reaction is used for the laboratory analysis of Uric acid?
Carraway reaction
What is the carraway reaction?
Reduction of phosphotungstic acid to tunsten blue
What can cause false negatives for the lab analysis of Uric Acid?
Bilirubin
Ascorbic acid
What is the reference range for Uric acid?
3-7 mg/dL
Is uric acid a very sensitive indicator for renal disease?
No
If levels of Uric Acid become high it might precipitate in tissues as what?
Monosodium Urate Crystals
If levels of Uric Acid become high it might precipitate in tubules as what?
Uric Acid Crystals
Gout
Precipitated urates (MSU) in joins cause pain and swelling
Gout is aggrevated by what?
diet
drugs
alcohol ingestion
Gout correlates with a tendency to form what?
Kidney Stones
What 3 Diseases correlate with Uric Acid?
Gout
Increased breakdown of cell nuclei
Renal disease
What are often associated with Increased breakdown of cell nuclei?
Chemotherapy for leukemia/lymphoma
Tumor Irradiation
Hemolytic anemias if WBC count is high
What are the prominent functions of the Renal system?
Waste removal
Water, Electrolyte, & Acid-Base Balance
Hormone Production
List the steps of Urine Formation & Waste Removal
1. Filtration by the glomerulus
2. Reabsorption by the proximal convoluted tubule
3. Secretion by the proximal convoluted tubule
4. Concentration in the distal convoluted tubules and collecting ducts
What occurs at the Loop of Henle?
Water, Na, and Cl reabsorption
What occurs at the Distal tubules/collecting ducts?
Sodium reabsorption
What is sodium reabsorption at the Distal tubules/collecting ducts influenced by?
Aldosterone
True or False:
Substances exceeding renal threshold cannot be reabsorbed
True
What is the defect in D. insipidus?
ADH/AVP
What is the defect in D. mellitus?
Insulin
True or False:
The Plasma osmolality and urine volume INCREASE for both D. insipidus & D. mellitus
True
Does Urine Osmolality Increase or Decrease for D. Insipidus?
Decrease
Does Urine Osmolality Increase or Decrease for D. Mellitus?
Increase
What element is the primary contributor to osmolality?
Sodium
As sodium moves in, what moves out to maintain electrical neutrality?
Potassium & Hydrogen
What will be exchanged to maintain Acid-Base Balance?
H+
HCO3
What will be reabsorbed along with Sodium?
Chloride
Why is Chloride reabsorbed along with Sodium?
Counter Ion
Define Clearance
The rate at which a substance is removed or cleared from the body
True or False:
Creatine is completely filtered and not reabsorbed
True
What is the standard measure for GFR?
Creatinine
When do you correct the Creatinine Clearance?
Big or little people
Elderly
Amputees
Muscle wasting diseases
What is the normal range of CrCl for Men/Women:
90-140 mL/min
What is the normal range of CrCl for Women:
90-130 mL/min
What is the normal range of CrCl for Children:
55-85 mL/min
What is the normal range of CrCl for Newborns:
35-65 mL/min
Name the 2 types of test for Creatinine where urine is NOT needed
eGFR
Cystatin C
What is the formula for eGFR (mL/min)?
((140-age)(weight in kg))/((72)(Serum Creatinine))
What do you multiply the eGFR by if the patient is female?
0.85
Cystatin C is unaffected by what?
Gender
Race
Muscle Mass
Age
True or False:
Cystatin C will be elevated in serum before GFR is decreased
True
What is a better predictor of developing kidney disease?
Cystatin C
What is Cystatin C?
Tiny protein produced by nucleated cells at a constant rate
What test do you perform to detect early renal disease in diabetics?
Microalbumin
Microalbumin will detect as little as ______ / 24 hours?
30-300 mg
Urine Dipstick is positive for Albumin at what concentration?
500 mg/24 hours
You perform the following Chemical Urinalysis Exam to determine what:
pH
Acid-Base Balance
You perform the following Chemical Urinalysis Exam to determine what:
Protein
Glomerular Disease
You perform the following Chemical Urinalysis Exam to determine what:
Blood
Renal Disease
Infection
Trauma
Stones
You perform the following Chemical Urinalysis Exam to determine what:
SG
Dehydration
What are the 6 Infections correlated with Renal Function
Acute Glomerulonephritis
Nephrotic Syndrome
Kidney Infection
Bladder Infection
Chronic Kidney Disease
Acute Renal Failure
What type of infection will you see WBCs & WBC CASTS
Kidney Infection
(Pyelonephritis)
What type of infection will you see WBCs, +/= nitrites, & Hematuria but NO WBC Casts
Bladder Infection
(Cystitis)
Which Disease will you find Massive Proteinuria and Lipiduria?
Nephrotic Syndrome
Which Disease will you find Oval fat bodies, fatty casts, and Cholesterol crystals?
Nephrotic Syndrome
What disease follows group A beta-hemolytic strep infection?
Acute Glomerulonephritis
The following are seen in what disease:
RBC casts, hematuria, proteinuria, and oliguria
Acute Glomerulonephritis
With which disease will you see abnormalities of structure or function that persist for more than 3 months?
Chronic Kidney Disease
Chronic Kidney Disease: GFR is what?
<60
What insufficiency are common in Chronic Kidney Disease?
Anemia
Vitamin D
What are the causes of Chronic Kidney Disease?
Glomerulonephritis
Polycystic Disease
SLE
Diabetes
Others
You will find albuminuria in what disease?
Chronic Kidney Disease
Which which disease will you find the following:
Tubular necrosis from transfusion reactions, poisoning, antifreeze, and other toxic exposures
Acute Renal Failure
Is Acute Renal Failure a sudden shut-down or a long shut-down?
Sudden
Acute Renal Failure from reduced blood flow is consistent with what?
Shock
Burns
Cardiac Problems
What does Acute Renal Failure lead to?
Electrolyte Imbalances
Water Retention
CHF
Arrhythmias
What decreases in Acute Renal Failure
GFR
Anuria
What will you find microscopically with Acute Renal Failure?
Renal tubular cells and casts
Waxy casts
Anemia
When ADH decreases what happens?
Reabsorption Decreases and Urine Increases
Osmolality
# of particles / kg of solvent
Name 3 Renal Hormones
Renin
Prostaglandins
Erythropoietin
What is the average GFR?
(Hint: it is the same as average adult CrCl)
120 mls/min
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