Final Flashcards
What is the difference between plasma and serum?
Plasma is the liquid portion of whole blood. Serum is the liquid portion of clotted blood.
What is the most common specimen used in chemistry testing?
Serum.
What type of tube will be used for serum and what type for plasma?
Serum- red top or serum separator tube SST. Plasma- green top with heparin.
How is serum collection done?
Blood is allowed to clot for 20-30 minutes and then centrifuged for 5-10 minutes. Serum should be separated from the cells within one hour after collection.
What happens if serum is separated from cells after 1 hour?
You can get erroneous results like falsely low glucose, and falsely high LDH and K. However this usually takes hours of sitting there.
What is hemolysis and what will it lead to?
Destruction of RBC’s and this liberates intracellular biochemicals creating falsely high serum LDH and K levels.
What is lipemic serum?
Serum which is hazy due to the presence of chylomicrons.
What causes lipemic serum?
Non-fasting specimen or an inherited ipoprotein metablosim abnormality (inability of the liver to clear the chylomicrons).
What are metabolites?
Toxic waste products that need to be removed.
What are substances that are released from cells as a result of cell damage, abnormal permeability, or abnormal cellular proliferation?
Enzymes.
Name 7 factors that affect glucose control?
- Stress. 2. Food consumption. 3. exercise. 4. HORMONES. 5. drugs. 6. Alcoholism. 7. Liver disease.
What effects will hormones have on glucose?
They all increase serum levels of glucose besides insulin which decreases the levels.
What will alcoholism do to glucose levels?
Short term- decrease. Long term can lead to diabetes.
Why will serum need to be separeted from the cells within one hour?
The blood cells will metabolize the glucose resulting in a loss of up to 5 mg/dl (1-2%) of glucose per hour.
When can serum go for more than one hour before being separated?
If refrigerated or if a gray top (sodium fluoride) tube is used.
With a random collected specimen what glucose levels will indicate diabetes mellitus?
> 200 mg/dl.
With a fasting collected specimen what glucose levels will indicate diabetes mellitus?
Greater than or equal to 126 mg/dl.
What is the reference value for glucose with a fasting specimen?
60-99 mg/dl.
How long should you fast before a fasting glucose test?
at leaste 8 hours but no more than 12-16.
What should not be done prior to glucose testing?
No smoking or exercise or undue stress and should be taken first thing in the morning.
The fasting glucose test is most useful for what?
To indicate overall glucose homeostasis.
What is a two-hour postprandial (after a meal) glucose test used for?
TO determine the body’s ability to control glucose levels following ingestion of food.
What is the two-hour oral glucose tolerance test used for?
Used historically to confirm suspected diabetes based upon clinical signs and symptoms.
What is the two-hour postload glucose test?
A 2 hour specimen alone is used as a single-screening test.
What test are recommended by the American Diabetic Association to test for diabetes?
Fasting plasma glucose, two-hour postload glucose.
What should be done if you get an abnormal result from a diabetes test?
Should be confirmed by a different test on another day.
Which test is best for type II and type I diabetes?
Type II- Fasting plasma glucose. Type I- two-hour postload glucose.
What are the names for high and low levels of glucose?
Hyperglycemia and hypoglycemia.
What are the most common causes of hyperglycemia?
Uncontrolled DM, Abnormal glucose metabolic states, pancreatic disorders (not making enough insulin), hyper-endocrineopathies (increases hormones and this increases glucose), acute stress, corticosteroid therapy, non-fasting specimen.
What are the most common causes of hypoglycemia?
insulinoma, insulin overdose, hypo-endocrinopathies, extensive liver disease, starvation.
The formation of urea nitrogen is associated with what?
Protein metabolism (primarily catabolism).
How is urea nitrogen made?
Catabolism of proteins liberates amino groups and they are transported to the liver and incorporated into urea.
How will urea be excreted?
It diffuses into extracellular fluid and is carried to the kidneys for excretion about 25 grams per day.
What is the short name for urea nitrogen?
Blood Urea Nitrogen BUN.
What type of product is BUN?
A non-protein nitrogenous waste product.
Plasma levels of BUN reflect what?
The balance between production (protein catabolism) and kidney function.
What is the name for increased plasma levels of BUN?
Azotemia.
What are the 3 types of azotemia?
Pre-renal, renal, post-renal.
What pre-renal things can lead to azotemia?
Prolonged high protein intake, dehydration/hypovolemia (decreasd plasma volume), and increased protein catabolism.
What are the renal things that can lead to azotemia?
Renal disease.
What are the post-renal things that can lead to azotemia?
Lower urinary tract obstructions.
What are the things that lead to low levels of BUN?
Expanded plasma volume, liver disease, pregnancy (plasma volume expands).
What is the end product of skeletal muscle metabolism?
Creatinine. NOT creatin.
Plasma levels of creatinine reflect what?
Skeletal muscle mass only not activity.
Creatinine enters the circulation and is removed how?
Removed from the plasma by the kidneys.
What type of product is creatinine?
A non-protein nitrogenous waste product.
Plasma levels of creatinine are proportional to what?
Skeletal muscle mass of the individual.
Increased creatinine and BUN levels are observed in patients with reduced kidney function of how much?
Reduced kidney function of over 50%.
Decreased creatinine levels are seen in patients with what?
Reduced muscle mass, most commonly seen in females and children.
What are the most common causes of increaed creatinine levels?
Renal disease, increased muscle mass.
What is the most common cause of decreased creatinine levels?
Decreased muscle mass.
Since creatinine has a steady state of production it is ideal for what?
for a clearance test of kidney function.
Clearance is measuered by UV/P which is what?
U- urine concentration of the analyte. V- volume of urine output in 24 hours. P- Plasma concentration of the analyte.
Creatinine clearance is considered a sensitive measurement of what?
Overall renal functional impairment.
What is the byproduct of purine metabolism?
Uric acid.
When will there be purine metabolism?
As RNA and DNA are synthesized and degraded.
Uric acid is synthesized where?
In the liver by enzymes.
What happens to uric acid as it enters the circulation?
it is filtered, partially reabsorbed and actively secreted into the urine by the kidneys.
Plasma levels of uric acid reflect what?
The balance of production and renal function.
What results in increased uric acid synthesis?
Increased levels of tissue breakdown.
What type of diet has purines in it and a dietary purine intake leads to what?
organ meats, legumes, and yeaste. A low purine diet halves the average daily production.
Decreased renal function does what to uric acid levels?
Increases it.
How can uric acid exretion be enhanced?
Pharmacologically.
What are the names for high and low levels of uric acid?
Hyperuricemia and hypouricemia.
What are the most common causes of hyperuricemia (increased production)?
Excess dietary purines, inherited abnormal purine metabolism, certain malignancies (breakdown tissues), chemotherapy.
What are the most common causes of hyperuricemia (decreased excretion)?
Idiopathic, renal disease, chemical induced (alcohol, asprin).
What are 3 tests for alcoholism?
Increasd Triglycerides and GGT’s and hyperuricemia.
What are the most common causes of hypouricemia (increased excretion)?
Chemical induced (asprin, estrogen, corticosteroids, warfarin).
What are the most common causes of hyouricemia (decreased production)?
Chemical induced (allopurinol).
What are the 4 electrolytes?
Sodium, potassium, chloride, CO2
Why are electrolytes important?
Water balance, acid-base balance, nerve conductivity and muscle contractility, and many other cellular functions.
Why would you order electrolyte tests?
Hospitalized patients: critical care, unstable and surgical patients on intravenous fluids. Outpatients especially those on diuretics and other medications that can alter the electrolyte balance.
What is the major intra and extra cellular cations?
Extracelluar- sodium. Intracellular- Potassium.
What are the 3 controls of sodium levels?
Dietary intake, renal excretion or retention, endocrine system (ADH, Aldosterone).
What are the names for high and low levels of sodium?
Hypernatremia, hyponatremia.
What are the most common causes of hypernatremia?
Increased sodium intake from diet (uncommon), decreased sodium loss (increasd aldosterone), excess water loss ( GI loss without rehydration excessive sweating dehydration).
What are the most common causes of hyponatremia?
Decreased sodium intake (rare), increased sodium loss (adrenal insufficiency prolonged vomiting/ diarrhea, diuretics, chronic renal insufficiency), increaed free body water (over-hydration congestive heart failure).
Hyponatremia can lead to signs and symptoms of what?
hypotension, shock, cardiac abnormalities, mental aberrations such as confusion.
What is the plasma level of potassium like?
Very low since it is an intracelluar electrolyte.
What function is greately influenced by potassium?
Neuromuscular contractility.
Potassium levels are critically important in what?
Patients with heart conditions.
How will the kidney regulate pH?
Shift K and H ions.
Very slight alterations of potassium serum levels are critical and can reflect what?
major intracellular potassium abnormalites.
What happens to potassium in the kidneys?
It is lost and cannot be reabsorbed.
Potassium levels are greatly influenced by what?
Aldosterone and sodium reabsorption and loss.
What are three things to think of with increased potassium levels?
Hemolysis- will release intracellular K. Venipuncture- can increase if tourniqet is left on too long or if you slap their arm by releasing K from platelets. Thrombocytosis- Platelets are rich in K and K is released into the serum with thrombocytosis.
What are the names for high and low levels of potassium?
Hyperkalemia, hypokalemia.
What are the most common causes for hyperkalemia?
Exess dietary intake, Dehydration, acute or chronic renal failure (most common), adrenal insufficency, hemolytic diseases, massive tissue injury or infection.
What are the most common causes for hypokalemia?
Dieatary deficiency, GI loss (prolonged vomiting/diarrhea, diuretics, hyper-adrenal conditions, licorice overdose.
Both hyper and hypo kalemai result in what?
Weakness and loss of deep tendon reflexes, disturbances of GI motility, and also mental aberrations.
What are the lethal consequences of hyper- or hypo- kalemia?
paralysis of respiratory muscles and cardiac arrest.
What is the major extracellular anion?
Chloride.
Chloride is responsible for what?
Maintaining electrical neutrality as a salt in combination with sodium.
Chloride is intimately involved in what?
Acid-base balance.
It is most common to see chloride changes associated with what?
Altered breathing as part of respiratory compensation for pH.
Chloride shifts parallel changes in what?
Sodium.
Alone chloride is of what clinical value?
Little always measured in combination with other electrolytes.
What are the names for high and low levels of chloride?
Hyperchloremia and hypochloremia.
What are the most common causes of hyperchloremia?
Dehydration, acidosis.
What are the most common causes of hypochloremia?
Overhydration, GI loss, alkalosis.
Why is bicarbonate dissolved not the same as pCO2?
Bicarbonate dissolved is CO2.
Bicarbonate has a very similar role as ____ in maintaining electrical neutrality/
Chloride.
Bicarbonate is regulated by what to maintain acid-base balance?
Kidneys.
What are serum levels of bicarbonate like?
They tend not to be accurate and therefore this test roughly reflects acid-base balance.
What are the most common causes of increased and decreased bicarbonate levels?
Increased- metabolic alkalosis. Decreased- metabolic acidosis.
CO2 content and related considerations are best evaluated how?
Via arterial blood gases.
How much of the total body calcium is stored in bones?
99%.
What are the important physiologic activities of clacium?
Blood coagulation, neuromuscular condiction, cell membrane function, regulation of glandular excretions, sekeletal and cardiac muscle contractility.
How will calcium circulate in the plasma and what will this mean?
As a cation and as such can be considered an electrolyte. About 50% of the calcium circulates bound to albumin and the other 50% is ionized calcium.
A routine serum calcium assay is actually what?
Total serum calcium.
What type of circulating calcium is the active portion?
The ionized calcium.
What is calcium that is bound to albumin like?
It is not physiologically active.
What is more common hypoalbuminemia or hyperalbuminemia?
Hypoalbuminemia.
Albumin altering conditions influence what?
The total amount of calcium but not the physiologically active ionized portion.
Can ionized calcium be assayed?
Yes via separately ordered test and is not part of a routine biochemical profile.
Ionized calcium is most useful in evalutaing what?
Hypocalcemia.
What hormone is responsible for controlling plasma levels of calcium?
PTH.
What will create an increased amount of PTH?
Hypocalcemia.
What will PTH do?
Osteoclastic bony resorption (take calcium from bones), decreases the loss of calcium in the urine, and enhances the absorption of calcium in the intestines. It will also help the kidneys make the active form of vitamin D.
What will vitamin D do?
enhances intestinal absorption of calcium and phosphorus and accelerate bony resporption.
How will Vitamin D be made from the sun?
Sun changes 7-dehydrocholesterol into cholecalciferol (D3), then D3 goes to the liver (so will Dietary intake of D3 and D2) and will be converted into 25-hydroxyvitamin D3. Then 25-hydroxyvitamin D3 will go to the kidney and with the help of PTH the kidney will convert it inot 1,25-dihydroxyvitamin D3 which maintains calcium balance in the body.
How will PTH decrease loss of calcium in the urine?
It promotes excretion of phosphate.
Alterations in PTH will affect what portion of calcium?
The ionized calcium.
What is the name for high and low levels of calcium?
Hypercalcemia and hypocalcemia.
What are the most common causes of hypercalcemia?
parathyroid disease (hyperparathyroidism), malignancies, granulomatous infections (TB, sarcoidosis), hyperthyroidism (thyroid hormone can increse osteoclastic activity), pancreatitis.
What are the most common causes of hypocalcemia?
Parathyroid disease (hypoparathyroidism), renal failure, vitamin D deficiency.
Hypocalcemia will happen at what level and what is the top limits of calcium?
Hypo- less than 7 mg/dl. Top limit- 10.5 mg/dl.
What are the signs of hypocalcemia?
Nervousness, excitability, tetany (uncontrolled total muscle contraction).
When will hypercalcemia be something to worry about?
if top limit is 10.5 then you should worry at 10.6.
What will happen with calcium levels at 11.5-12.0 mg/dl?
Fatigue, depression, vague GI (nausea, vomit, anorexia, constipation).
What will happen with calcium levels at 12.0-13.0 mg/dl?
Calcification of soft tissues.
What will happen with calcium levels greater than 13.0 mg/dl?
Medical emergency.
In general what will phosphorus do?
The opposite of calcium.
How is phosphorus measured?
As inorganic phosphate.
what % of total body phosphorus is stored with calcium in bones?
85%.
Increased calcium will do what to phosphorus?
Decrease it and decreased calcium will increase phosphorus.
What is the name for high and low levels of phosphorus?
Hyperphosphatemia and hypophosphatemia.
What are the most common causes of hyperphosphatemia?
parathyroid disease (hypoparathyroidism), renal failure, High phosphate diet, malignancy of bone.
What is the most common cause of hypophosphatemia?
Parathyroid disease (hyperparathyroidism).
What are the 4 tests for serum proteins?
- Total protein. 2. Albumin. 3. Globulins. 4. A/g ratio.
What are the main types of circulating proteins?
Albumin and globulins.
How helpful is a total protein test alone?
Not very you need an albumin or globulins test to go with it.
Albumin by weight is the_______________________.
largest single fraction of plasma proteins even though it is a small molecule.
Where is albumin made at and what can this be helpful for?
In the liver and it can be used as a liver function test LFT.
What is the major responsibility of albumin?
To create osmotic pressure of blood plasma.
Albumin acts as a circulating reservoir of what?
Amino acids.
What is another role of albumin?
Acts as a carrier protein.
How common is hyeralbuminemia and what causes it?
It is rare and is caused by overt clinicla dehydration.
Hypoalbuminemia is associated with what?
reduced synthesis, increased loss, increased catabolism.
What is the most common cause of hyperalbuminemia?
decreased plasma volume.
What are the most common causes of hypoalbuminemia?
Reduced synthesis (liver disease), increased loss (protein-losing nephropathies, protein-losing enteropathies), increased catabolism (widespread cancer).
What are globulins?
Total protein minus albumin.
How many groups of globulins are there and what are the groups based on?
4 and they are based upon electrophoretic mobility.
What will the clinical significance of hypo- and hyper-globulinemai be reatled to?
Which globulin accounts for the increase or decrease.
What are the 4 groups of globulins?
Alpha-1-globulins. Alpha-2-globulins. Beta globulins, Gamma globulins.
What are the types of alpha-1 globulins and what are there %?
Alpha-1-antitrypsin (AAT)- 90%. Alpha-fetoprotein (AFP)- 10%.
What type of protein is the alpha-1-antitrypsin?
Acute phase reactant.
What is an acute phase reactant protein?
one that is created as a reaction to the acute phase and they are protease inhibitors.
What are protease inhibitors?
they keep inflammatory responses in check.
What is the main reason for increased alpha-1-antitrypsin?
Inflammatory diseases.
What is the most common cause for decreased levels of alpha-q-antitrypsin?
Inherited deficiencies associated with juvenile pulmonary emphysema.
What are plasma levels like for alpha-fetoprotein?
Major plasma protein in the fetus but minute levels in the adult.
What are increased levels of alpha-fetoprotein associated with?
certain malignancies or seen during pregnancy with a neural tube defect and down’s syndrome.
Name the only alpha-2-globulin mentioned in the notes?
Haptoglobin.
What is the most common cause for increased alpha-2-globulins?
An acute phase reaction to an acute inflammatory disease.