Clinical Chemistry Part 1

Front 1

obstructive jaundice (cholestasis): Definition and causes

Back 1

an interruption to the drainage of bile in the biliary system.

Front 2

Obstructive jaundice: Causes

Back 2

Causes are gallstones in the common bile duct, and pancreatic cancer in the head of the pancreas. Also, liver flukes.

Front 3

Obstructive jaundice: symptoms

Back 3

pale stools and dark urine suggests an obstructive or post-hepatic cause as normal feces get their color from bile pigments. Patients often complain of severe itching.

Front 4

biliary cirrhosis: definition

Back 4

An autoimmune disease of the liver marked by the slow progressive destruction of the small bile ducts (bile canaliculi) within the liver

Front 5

biliary cirrhosis: causes

Back 5

bile builds up in the liver (cholestasis), This can lead to scarring, fibrosis, cirrhosis, and ultimately liver failure.

Front 6

biliary cirrhosis: symptoms

Back 6

fatigue, itchy skin, jaundice, cirrhosis, flid retention

Front 7

biliary cirrhosis: Diagnosis

Back 7

high alkaline phosphatase, elevated AST, ALT. Presence of certain antibodies:(the M2-IgG antimitochondrial antibody is the most specific test)

Front 8

viral hepatitis:

Back 8

Liver inflamation, may lead to cirrhosis or Hepatocellular carcinoma. Diagnoised via CT scan and biopsy

Front 9

azotemia:

Back 9

too much urea in the blood,

Front 10

bilirubin: Definition

Back 10

a yellow breakdown product of normal heme catabolism. It is responsible for the yellow colour of bruises and the brown colour of feces

Front 11

Bilirubin: Biosynthesis

Back 11

Biliverdin, a product of heme breakdown, is converted to biliruben by biliverdin reductase

Front 12

Bilirubin: Toxicity

Back 12

neonatals are at risk for neuronal damage due to Kernicterus

Front 13

Bilirubin: function

Back 13

main physiologic role is as a cellular antioxidant

Front 14

Bilirubin: metabolism (spleen-liver)

Back 14

heme is converted to bilirubin in the spleen then bound to albumin and sent to the liver then conjugated with glucuronic acid, making it water soluble

Front 15

In the liver, bilirubin is converted to:

Back 15

bilirubin diglucuronide

Front 16

Bilirubin: metabolism (small and large intestine)

Back 16

Much goes into bile and into the small intestine. In the large intestine metabolized by bacteria into stercobilinogen and then oxidised to stercobilin

Front 17

Bilirubin: excretion

Back 17

Resorbed in LI and excreted in the urine as urobilinogen and the oxidised form, urobilin.

Front 18

Bilirubin blood tests

Back 18

broken down by light, and therefore blood collection tubes (especially serum tubes) should be protected from such exposure.

Front 19

Biuret reaction: Definition

Back 19

potassium hydroxide (KOH) and copper (II) sulfate (CuSO4), together with potassium sodium tartrate turn from blue to violet in proteins

Front 20

Biuret reaction: Function

Back 20

a colorimetric assay used to determine protein concentration--such as UV-VIS at wavelength 560nm

Front 21

Hemoglobin: Definition

Back 21

The iron-containing oxygen-transport metalloprotein in the red blood cells of the blood. Makes up about 97% of the red cell’s dry content.

Front 22

Total iron-binding capacity: definiton

Back 22

A test which measures the extent to which iron-binding sites in the serum can be saturated. Transferrin.

Front 23

Transferrin: Definition

Back 23

a blood plasma protein for iron ion delivery. Glycoprotein.

Front 24

Transferrin: Mechanism

Back 24

Binds two irons. Encounters transferrin receptor, transported into cell, removed iron. Affinity decreases with pH

Front 25

Transferrin: Function

Back 25

less than 0.1% (4 mg) of the total body iron. Highest turnover rate in the iron pool.

Front 26

ceruloplasmin: Definiton

Back 26

an enzyme synthesized in the liver containing 8 atoms of copper in its structure. Ceruloplasmin carries 90% of plasma copper

Front 27

Ceruloplasmin: Decreased levels indicate?

Back 27

"Menkes disease-kinky hair
"Menkes disease-kinky hair
Wilson's disease
Overdose of vitamin C
Copper deficiency

Front 28

Ceruloplasmin: Elevated levels indicate?

Back 28

pregnancy
lymphoma
acute and chronic inflammation
rheumatoid arthritis

Front 29

ferritin: definition

Back 29

a globular protein. Main intracellular iron storage protein. Serum levels directly correlated with the total amount of iron stored

Front 30

urobilin: definiton

Back 30

a yellow linear tetrapyrrole, resulting from the breakdown of heme. generated in intestines from bilirubin.

Front 31

urobilinogen: definition

Back 31

a colourless product of bilirubin reduction.

Front 32

Urobilinogen: Biosynthesis

Back 32

It is formed in the intestines by bacterial action. in liver disease is converted to the yellow pigmented urobilin apparent in urine.

Front 33

stercobilinogen: Definition

Back 33

urobilinogen remaining in the intestine. Is oxidized to brown stercobilin which gives the feces their characteristic color

Front 34

azobilirubin: defintion

Back 34

Used in the In the Jendrassik-Grof method for serum bilirubin. Green color.

Front 35

bilirubin glucuronide: Definition

Back 35

Bilirubin conjugated with glucuronic acid to become water soluable.

Front 36

Aspartate aminotransferase : Definiton

Back 36

It facilitates the conversion of aspartate and alpha-ketoglutaric acid to oxaloacetate and glutamate.

Front 37

alanine aminotransferase: Definition

Back 37

catalyzes transfer of amino group from alanine to a-ketoglutarate, the products of this reversible transamination reaction being pyruvate and glutamate.

Front 38

alanine aminotransferase: Elevated levels indicate?

Back 38

viral hepatitis, congestive heart failure, liver damage, biliary duct problems, infectious mononucleosis, or myopathy. ALT is commonly used screening for liver problems

Front 39

Aspartate aminotransferase: Elevated levels indicate?

Back 39

acute liver damage

Front 40

Formula for Anion Gap

Back 40

"1.86 + glucose + BUN +9
------- ---
18 28"

Front 41

Normal Anion Gap

Back 41

8-16 mMOl/L

Front 42

partial alveolar CO2 pressure

Back 42

40 mm Hg

Front 43

partial alveolar O2 pressure

Back 43

99.92 mm Hg

Front 44

Normal H+ concentration in the blood

Back 44

40 nMol/L

Front 45

Henderson Has. equation for acid base

Back 45

"pH = pKa- log [total Co2 - .03 pCo2]/[.03 p Co2]

pKa = 6.1"

Front 46

Buffers in body

Back 46

"1) proteins
2) PO4 (40%)
3) HCO3 (60%)"

Front 47

Definition of anion gap

Back 47

difference between the usually unmeasured cations and the unmeasured anions

Front 48

Definition of Buffer capacity

Back 48

"Amt of base consumed before upper limit of pH is reached

amt of acid consumed before lower limit of pH is reached"

Front 49

normal osmalality

Back 49

less than 10 mOsm

Front 50

formula for osmalality

Back 50

"1.86 + glucose + BUN +9

Front 51

HCO3 levels

Back 51

"Plasm ISF Cell
128 31 8"

Front 52

O2 saturation

Back 52

% total hemoglobin present as oxygenated hemoglobin

Front 53

osmotic pressure depends on:

Back 53

the total number of solute particles in solution

Front 54

definition of ascites

Back 54

leakage of fluids out of vascular space into peritoneal space

Front 55

increase in dissolved particles:

Back 55

"decreases freezing point
decreases vapor pressure
increases osmotic pressure
increases boiling point"

Front 56

hypotonic vs hypertonic

Back 56

"hypertonic: more H2O inside
cell
H2o goes out
cells shrink
Hyptonic:
more H2O outside
cells swell"

Front 57

Normal range of Na+

Back 57

80--180 mg/dL

Front 58

redistribution caused by:

Back 58

"acidosis
insulin deficiency
Beta Blockers
digitalis"

Front 59

Excretion of H+

Back 59

"1) Rxn filtered buffers
2) filtered bicarb
3) Rx with NH3
4) electrolyte exchange"

Front 60

Explain the rationale for performing serum osmolality assays.

Back 60

Osmolality assays tell us the osmotic pressure which is exerted by all of the solutes in a solution

Front 61

Expected ranges for serum and urine osmolality assays

Back 61

Serum- 289-308 mOsm/kg, Urine: 300-900 mOsm/kg: A healthy persons urine osmolality should be up to 3 times greater than their serum; Reference range of serum to urine osmolality is 1.0 to 3.0; A ratio of 1.0 says the nephrons aren't doing anything to the urine

Front 62

Describe how alterations in blood osmotic pressure can cause dehydration, edema, and hypertension.

Back 62

"If blood osmolality increases fluid will be drawn into the blood from the interstitial fluid causing hypertension and dehydration. If blood osmolality is decreased water will be drawn into the interstitial compartment causing hypotension and edema"

Front 63

Osmolal Gap explanation and equation

Back 63

Osmolal gap is the difference between measured osmolality with an osmometer vs. the calculated osmolality
Osmol gap= (mmol Na+)(1.86) + (Glucose mg/dl)/(18) + (BUN mg/dl)/(2.8)
normal gap is 0-20 mmol/L

Front 64

Explain the principles of freezing-point depression osmometers

Back 64

"Uses serum or urine and super cools the sample to -7 c. The sample is vibrated rapidly to release the heat of fusion that has been trapped during the rapid cooling. As this is released the sample reaches its freezing point and the temp is measured.
the degree of freezing-point depression below that of pure water is directly proportional to the total number of particles in the solution; This is the preferred type for drug toxicology screening"

Front 65

Explain the principles of vapor pressure depression osmometers

Back 65

Most common method for plasma and urine osmolality.
The presence of solute in an aqueous solution reduces the evaporation of the water and exhibits an inverse relationship of concentration and vapor pressure.
These types under-quantitate highly volume

Front 66

Explain the principles of colloid osmotic pressure osmometers

Back 66

Proteins have a significant effect on osmotic pressue in vivo, but in vitro they aren't measured "worth a darn" in a VP or FP depression osmometer

Front 67

What is the normal fasting blood glucose range? How is this level maintained by insulin and glucagon

Back 67

"Normal fasting- 70-119 mg/dL; Insulin is the ONLY hormone that lowers blood sugar by allowing glucose to be transported into adipose and muscle cells
; Glucagon is the PRIMARY hormone which replenishes glucose levels; all other hormones serve to ELE"

Front 68

Explain why severe hepatitis, hypothyroid disease, and addison's disease may cause abnormally low blood glucose levels

Back 68

"Hepatitis- liver cannot store adequate amounts of glycogen to meet the body's need for glucose reserves
Hypothyroid- insufficient production of T3 and T4 results in inadequate lipolysis and glycogenolysis
Addison's- lack of cortisol production hinders glycogenolysis and gluconeogenesis"

Front 69

Major clinical features of Type 1 diabetes -IDDM

Back 69

"pronounced glycosuria; Very little to no insulin (insulin shock); Severe metabolic acidosis
; extremely high blood levels of ketone bodies"

Front 70

Major clinical features of Type 2- NIDDM

Back 70

Type 2 is the MILD version
: Normal insulin levels, Glycosuria is mild
, MILD ketones

Front 71

Limitations to OGTT

Back 71

Only limitation is the patient's ability to absorb glucose, Any form of malabsorption will cause erroneous results, If patient has malabsorption Intravenous glucose tolerance test must be substituted

Front 72

Explain FBS test

Back 72

Useful screeing test for all CHO disorders, Following a 12hr fast the blood glucose reflect the interaction of insulin production and glucagon production

Front 73

Explain 2hr Postprandial Test

Back 73

"quick and dirty screen
, if abnormal an OGTT may still be needed; Patient eats a regular mixed meal and 2 hrs later glucose is measured
, If glucose is greater than 200mg/dl it is diagnostic of DM
, Main problem is that the sugar challenge is NOT ST"

Front 74

Explain glycosylated Hgb test

Back 74

"Useful test for ALL CHO disorders; Also called Hemoglobin A1-c and Glycated Hemoglobin
; DOES NOT measure blood glucose but it estimates what the patients glucose level has been for the PREVIOUS 4-6 WEEKS. sort of a TIME AVERAGED glucose value "

Front 75

Explain Insulin Assay

Back 75

Done to distinguish between Type 1 and Type 2

Front 76

Criteria for GDM confirmatory Test

Back 76

"3HGTT. GDM is confirmed if any 2 of the following limits are exceeded: FBS greater than 105 mg/dl, 1hr >190 mg/dl
, 2hr >165 mg/dl, 3hr >145 mg/dl"

Front 77

Normal values for Hg A1-c

Back 77

5-9%

Front 78

Critical values for serum or plasma glucose in kids and adults

Back 78

"Below 40 mg/dl- brain damage
Above 450 mg/dl- diabetic coma"

Front 79

Critical values for serum or plasma glucose for newborn- 6 weeks

Back 79

"Below 30 mg/dl- brain damage
Above 300 mg/dl- diabetic coma"