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79 Cards in this Set
- Front
- Back
obstructive jaundice (cholestasis): Definition and causes
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an interruption to the drainage of bile in the biliary system.
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Obstructive jaundice: Causes
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Causes are gallstones in the common bile duct, and pancreatic cancer in the head of the pancreas. Also, liver flukes.
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Obstructive jaundice: symptoms
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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.
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biliary cirrhosis: definition
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An autoimmune disease of the liver marked by the slow progressive destruction of the small bile ducts (bile canaliculi) within the liver
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biliary cirrhosis: causes
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bile builds up in the liver (cholestasis), This can lead to scarring, fibrosis, cirrhosis, and ultimately liver failure.
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biliary cirrhosis: symptoms
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fatigue, itchy skin, jaundice, cirrhosis, flid retention
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biliary cirrhosis: Diagnosis
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high alkaline phosphatase, elevated AST, ALT. Presence of certain antibodies:(the M2-IgG antimitochondrial antibody is the most specific test)
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viral hepatitis:
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Liver inflamation, may lead to cirrhosis or Hepatocellular carcinoma. Diagnoised via CT scan and biopsy
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azotemia:
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too much urea in the blood,
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bilirubin: Definition
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a yellow breakdown product of normal heme catabolism. It is responsible for the yellow colour of bruises and the brown colour of feces
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Bilirubin: Biosynthesis
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Biliverdin, a product of heme breakdown, is converted to biliruben by biliverdin reductase
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Bilirubin: Toxicity
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neonatals are at risk for neuronal damage due to Kernicterus
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Bilirubin: function
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main physiologic role is as a cellular antioxidant
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Bilirubin: metabolism (spleen-liver)
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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
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In the liver, bilirubin is converted to:
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bilirubin diglucuronide
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Bilirubin: metabolism (small and large intestine)
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Much goes into bile and into the small intestine. In the large intestine metabolized by bacteria into stercobilinogen and then oxidised to stercobilin
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Bilirubin: excretion
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Resorbed in LI and excreted in the urine as urobilinogen and the oxidised form, urobilin.
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Bilirubin blood tests
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broken down by light, and therefore blood collection tubes (especially serum tubes) should be protected from such exposure.
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Biuret reaction: Definition
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potassium hydroxide (KOH) and copper (II) sulfate (CuSO4), together with potassium sodium tartrate turn from blue to violet in proteins
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Biuret reaction: Function
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a colorimetric assay used to determine protein concentration--such as UV-VIS at wavelength 560nm
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Hemoglobin: Definition
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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.
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Total iron-binding capacity: definiton
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A test which measures the extent to which iron-binding sites in the serum can be saturated. Transferrin.
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Transferrin: Definition
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a blood plasma protein for iron ion delivery. Glycoprotein.
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Transferrin: Mechanism
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Binds two irons. Encounters transferrin receptor, transported into cell, removed iron. Affinity decreases with pH
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Transferrin: Function
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less than 0.1% (4 mg) of the total body iron. Highest turnover rate in the iron pool.
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ceruloplasmin: Definiton
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an enzyme synthesized in the liver containing 8 atoms of copper in its structure. Ceruloplasmin carries 90% of plasma copper
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Ceruloplasmin: Decreased levels indicate?
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"Menkes disease-kinky hair
"Menkes disease-kinky hair Wilson's disease Overdose of vitamin C Copper deficiency |
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Ceruloplasmin: Elevated levels indicate?
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pregnancy
lymphoma acute and chronic inflammation rheumatoid arthritis |
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ferritin: definition
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a globular protein. Main intracellular iron storage protein. Serum levels directly correlated with the total amount of iron stored
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urobilin: definiton
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a yellow linear tetrapyrrole, resulting from the breakdown of heme. generated in intestines from bilirubin.
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urobilinogen: definition
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a colourless product of bilirubin reduction.
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Urobilinogen: Biosynthesis
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It is formed in the intestines by bacterial action. in liver disease is converted to the yellow pigmented urobilin apparent in urine.
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stercobilinogen: Definition
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urobilinogen remaining in the intestine. Is oxidized to brown stercobilin which gives the feces their characteristic color
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azobilirubin: defintion
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Used in the In the Jendrassik-Grof method for serum bilirubin. Green color.
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bilirubin glucuronide: Definition
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Bilirubin conjugated with glucuronic acid to become water soluable.
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Aspartate aminotransferase : Definiton
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It facilitates the conversion of aspartate and alpha-ketoglutaric acid to oxaloacetate and glutamate.
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alanine aminotransferase: Definition
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catalyzes transfer of amino group from alanine to a-ketoglutarate, the products of this reversible transamination reaction being pyruvate and glutamate.
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alanine aminotransferase: Elevated levels indicate?
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viral hepatitis, congestive heart failure, liver damage, biliary duct problems, infectious mononucleosis, or myopathy. ALT is commonly used screening for liver problems
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Aspartate aminotransferase: Elevated levels indicate?
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acute liver damage
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Formula for Anion Gap
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"1.86 + glucose + BUN +9
------- --- 18 28" |
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Normal Anion Gap
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8-16 mMOl/L
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partial alveolar CO2 pressure
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40 mm Hg
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partial alveolar O2 pressure
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99.92 mm Hg
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Normal H+ concentration in the blood
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40 nMol/L
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Henderson Has. equation for acid base
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"pH = pKa- log [total Co2 - .03 pCo2]/[.03 p Co2]
pKa = 6.1" |
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Buffers in body
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"1) proteins
2) PO4 (40%) 3) HCO3 (60%)" |
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Definition of anion gap
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difference between the usually unmeasured cations and the unmeasured anions
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Definition of Buffer capacity
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"Amt of base consumed before upper limit of pH is reached
amt of acid consumed before lower limit of pH is reached" |
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normal osmalality
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less than 10 mOsm
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formula for osmalality
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"1.86 + glucose + BUN +9
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HCO3 levels
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"Plasm ISF Cell
128 31 8" |
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O2 saturation
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% total hemoglobin present as oxygenated hemoglobin
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osmotic pressure depends on:
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the total number of solute particles in solution
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definition of ascites
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leakage of fluids out of vascular space into peritoneal space
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increase in dissolved particles:
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"decreases freezing point
decreases vapor pressure increases osmotic pressure increases boiling point" |
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hypotonic vs hypertonic
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"hypertonic: more H2O inside
cell H2o goes out cells shrink Hyptonic: more H2O outside cells swell" |
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Normal range of Na+
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80--180 mg/dL
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redistribution caused by:
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"acidosis
insulin deficiency Beta Blockers digitalis" |
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Excretion of H+
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"1) Rxn filtered buffers
2) filtered bicarb 3) Rx with NH3 4) electrolyte exchange" |
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Explain the rationale for performing serum osmolality assays.
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Osmolality assays tell us the osmotic pressure which is exerted by all of the solutes in a solution
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Expected ranges for serum and urine osmolality assays
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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
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Describe how alterations in blood osmotic pressure can cause dehydration, edema, and hypertension.
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"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"
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Osmolal Gap explanation and equation
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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 |
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Explain the principles of freezing-point depression osmometers
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"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" |
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Explain the principles of vapor pressure depression osmometers
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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 |
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Explain the principles of colloid osmotic pressure osmometers
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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
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What is the normal fasting blood glucose range? How is this level maintained by insulin and glucagon
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"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" |
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Explain why severe hepatitis, hypothyroid disease, and addison's disease may cause abnormally low blood glucose levels
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"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" |
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Major clinical features of Type 1 diabetes -IDDM
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"pronounced glycosuria; Very little to no insulin (insulin shock); Severe metabolic acidosis
; extremely high blood levels of ketone bodies" |
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Major clinical features of Type 2- NIDDM
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Type 2 is the MILD version
: Normal insulin levels, Glycosuria is mild , MILD ketones |
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Limitations to OGTT
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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
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Explain FBS test
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Useful screeing test for all CHO disorders, Following a 12hr fast the blood glucose reflect the interaction of insulin production and glucagon production
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Explain 2hr Postprandial Test
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"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" |
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Explain glycosylated Hgb test
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"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 " |
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Explain Insulin Assay
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Done to distinguish between Type 1 and Type 2
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Criteria for GDM confirmatory Test
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"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" |
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Normal values for Hg A1-c
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5-9%
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Critical values for serum or plasma glucose in kids and adults
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"Below 40 mg/dl- brain damage
Above 450 mg/dl- diabetic coma" |
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Critical values for serum or plasma glucose for newborn- 6 weeks
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"Below 30 mg/dl- brain damage
Above 300 mg/dl- diabetic coma" |