Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Clinical Chemistry > Non-Protein Nitrogen > Flashcards

Non-Protein Nitrogen Flashcards

(59 cards)

Start Studying
1
Q

What are Proteins (CHON)?

A

Made up of carbon, hydrogen, oxygen, and nitrogen (CHON, CHO=carbohydrates). The Building Blocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

WHAT ARE BLOOD NITROGEN COMPOUNDS (CHON + NPN)?

A

Made up of proteins (building blocks) and non-protein nitrogenous compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Total Nitrogen?

A

Measures all chemically bound nitrogen in the sample (can be applied to biological samples like plasma and urine)

UREA and NITROGEN are measures

Useful in assessing nitrogen balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

HOW TO QUANTITATE NPN?

A

Whole Blood + Protein Precipitants = Protein-Free Filtrate (PFF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When did NPN originate?

A

originated in the early days of Clinical Chemistry when analytical methods require removal of CHONs before analysis (not done anymore though)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Clinically Significant NPN Compounds

A

Urea
Amino Acids
Uric acid
Creatinine
Creatine
Ammonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

% of total Protein (Urea)

A

45-50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

% of total Protein (Amino Acids)

A

25

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

% of total Protein (Uric Acid)

A

10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

% of total Protein (Creatinine)

A

5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

% of total Protein (Creatine)

A

1-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

% of total Protein (Ammonia)

A

0-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is BLOOD UREA NITROGEN (BUN)?

A

Major excretory product of CHON metabolism

BUN because historic assays for measuring urea were based on the N content in urea. Urea N has been used to refer to urea determination (indirect measurement)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

REASONS WHY PLASMA UREA IS MEASURED

A
  1. Evaluate renal function
  2. Assess hydration status
  3. Determine N balance
  4. Aid in the Dx. of renal dss
  5. Verify adequacy of dialysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

REFERENCE RANGE FOR UREA

A

6-20 mg/dL

↑w/ age. Children have lower values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is UREMIA?

A

Failure of excretory, regulatory & endocrine
function of the kidney

(If left untreated, it can progress to stupor, coma &
death. Treatment = dialysis and kidney transplant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is AZOTEMIA?

A

The INCREASE in BUN, CREA & other products of CHON metabolism

(A symptom of UREMIA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

THREE MAIN CATEGORIES OF ↑ UREA

A

PRERENAL

RENAL

POSTRENAL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

PRERENAL

A

A. ↓ in blood flow = less blood is delivered to the kidney = less urea is filtered
● Congestive heart failure
● Surgical shock
● Hemorrhage
● Dehydration

B. ↑ amount of CHON metabolism
● Stress
● Fever
● Major illness
● Corticosteroid therapy
● G.I hemorrhage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

RENAL

A

About KIDNEYS
● Acute & chronic renal failure
● Glomerular nephritis
● Tubular necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

POSTRENAL

A

AFTER KIDNEYS
● Renal calculi (or kidney stones)
● Prostate or bladder tumor
● Severe infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

THREE MAIN CATEGORIES OF ↓ UREA

A

↑ CHON (protein) synthesis

↓ CHON intake

↓ UREA formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

↑ CHON (protein) synthesis

A

As indicates of late pregnancy and infancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

↓ CHON intake

Study These Flashcards
A

STARVATION and malnutrition

25
↓ UREA formation
Liver Disease
26
UREA NITROGEN / CREATININE RATIO
This ratio normally at 10:1 to 20:1 aids differentiation of the cause of abnormal urea concentration.
27
Cause: Prerenal Azotemia
Urea: ↑ Creatinine: N° Ratio: ↑
28
Cause: Renal Azotemia
Urea: ↑ Creatinine: ↑ Ratio: N°
29
Cause: Postrenal Azotemia
Urea: ↑ Creatinine: ↑ Ratio: ↑
30
Cause: ↓ Urea Production (ie. acute tubular necrosis)
Urea: ↓ Creatinine: N° Ratio: ↓
31
Ammonia (Site)
Primary site of ammonia (NH3) is in the small intestine
32
3 routes of formation of ENDOGENOUS NH3 (ammonia produced by the body):
1. By-product of CHON metabolism 2. Urea reenters small intestine for microbial breakdown 3. Some results from anaerobic metabolism in skeletal muscle during exercise
33
Primary Causes of ↑NH3 in Adults
Hepatic encephalopathy Renal Failure Pulmonary Problems Reye's Syndrome Any abnormality in Krebs-Henseleit Cycle
34
Hepatic encephalopathy
Venous blood doesn’t pass through the liver in large enough quantities for detoxification Personality changes develop, neurological alterations appear & coma as end result of liver damage May involve liver necrosis or cirrhosis
35
Renal failure
Inability to excrete sufficient urea & NH3
36
Pulmonary problems
Secondary to altered blood pH, w/c distorts equilibrium between NH3 (ammonia) & NH4+ (ammonium)
37
Reye's Syndrome
● Acute metabolic liver disorder ● Occurs most commonly in children ● Serious disease that can be fatal ● Preceded by viral infection & AD of aspirin
38
Any abnormality in Krebs-Henseleit Cycle
impaired metabolism (hereditary disorders in urea cycle enzymes)
39
Uric Acid (BUA = BLOOD URIC ACID)
End product of purine nucleoside catabolism Main Sources: endogenous purines and dietary purines
40
Endogenous Purines?
Adenosine & Guanosine nucleotides from tissue destruction
41
Dietary Purines?
from the breakdown of ingested nucleic acids; what we eat
42
How Uric acid is made?
ENDOGENOUS PURINES + DIETARY PURINES → [goes to] LIVER → [and converted to] URIC ACID → (400mg from endogenous purines + 300mg from dietary purines) [will go to] → BLOODSTREAM → (although reabsorbed in the proximal convoluted tubule) 50% of total BUA is secreted in the urine.
43
URIC ACID PATHWAYS AFTER going to the BLOODSTREAM: (FOR 70% BUA ELIMINATION IN RENAL EXCRETION)
KIDNEY → most of the uric acid are filtered → 98-100% are reabsorbed in the Proximal Convoluted Tubules → about 40% is reabsorbed in the Distal Convoluted Tubules through active transport processes → only 6-12% Uric Acid is excreted in the urine (400-500 mg/dL)
44
URIC ACID PATHWAYS AFTER going to the BLOODSTREAM: (FOR REMAINING 30% IN RENAL EXCRETION)
INTESTINES → degradation by bacterial enzymes (in stool exam) → 200-500mg eliminated in the stool
45
What is URIC ACID in PLASMA present as?
Monosodium urate
46
Importance of MEASUREMENT OF BUA
Provides useful info for: 1. Gout - to confirm diagnosis and monitoring 2. Chemotherapy Patients - for monitoring to prevent uric acid nephropathy or nephrotoxicity 3. Inherited disorders of Purine Metabolism – assessment 4. Kidney disfunction – detect 5. Renal calculi – assist diagnosis (specifically uric acid stone)
47
Reference Range for URIC ACID ↑ synthesis of purine precursors = ↑ uric acid (↑ input = ↑ output)
MALE up to 7.0 mg/dL FEMALE up to 6.0 mg/dL
48
What is URICEMIA?
INCREASED URIC ACID in the blood
49
CAUSES OF HYPERURICEMIA
1. Alcohol and excess dietary purine intake 2. Gout 3. Tissue Hypoxia 4. Increased NA turnover when there is increased metabolism of cell nuclei 5. Inherited disorders of purine metabolism 6. Increased renal absorption 7. Decreased excretion 8. Thiazide diuretics 9. Lead poisoning 10. Starvation 11. Hemolytic or megaloblastic anemia 12. Bone disease
50
CAUSES OF HYPOURICEMIA
1. Secondary to liver disease 2. Fanconi syndrome – defective reabsorption in PCT 3. Chemotreatment w/ 6-mercaptopurine or azathioprine 4. Overtreatment w/ allopurinol (treatment for increase in uric acid) 5. Exposure to toxic agents
51
Creatinine is a function of:
a. Relative muscle mass – higher muscle mass, the higher creatinine production. An obese individual can be expected to have lower creatinine than non obese individual with the same body mass. b. Rate of creatine turnover c. Renal function (> 6-8% eliminated by PCT secretion)
52
Creatinine is a function of:
a. Relative muscle mass – higher muscle mass, the higher creatinine production. An obese individual can be expected to have lower creatinine than non obese individual with the same body mass. b. Rate of creatine turnover c. Renal function (> 6-8% eliminated by PCT secretion)
53
CREATINE AND CREATININE (CREA)
Crea means CREATININE in requisition slips, not CREATINE (We measure the former)
54
CREA and GFR (Glomerular Filtration Rate)
CREA is inversely proportional to GFR and although an imperfect measurement, it is commonly used to assess renal filtration function (Always better to use GFR)
55
Importance of MEASUREMENT OF CREA
Provides info for: ● Determining sufficiency of kidney function ● Monitor organ function after transplantation ● Determining severity of kidney disease ● Monitor progression of kidney disease ● ↑ CREA = obstruction or interferences w/ glomerular filtration ● CREA is inversely proportional to GFR ● ↑ CREA = ↓ GFR (even if not measured) = renal damage ● CREA is an insensitive marker, may not be measurably ↑ until >50% renal function has deteriorated
56
What is Creatine?
Precursor of Creatinine (CREA)
57
Importance of MEASUREMENT OF CREATINE
Used in: ● To evaluate Muscle Disease = ↑ creatine, ↑ urinary CREA, N° (Normal) CREA in blood ● Used for assessment of: - Muscular dystrophy - Poliomyelitis - Hyperthyroidism - Trauma ● Measurement of CK is better for Diagnosis bec. creatine measurement is usually not available in clinical laboratories
58
Importance of MEASUREMENT OF URINE CREA
Used in: ● A measure of completeness of 24-hr urine ● Urinary constituents may be expressed as a ratio to creatinine quantity rather as mass excreted per day
59
What does Blood Urea Nitrogen (BUN) measure?
Measures Ammonia instead of Urea

Clinical Chemistry (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions