The Complete Metabolic Panel (CMP) Flashcards
What are common indications of the CMP?
- measurement of kidney function
- measurement of liver function
- measurement of electrolytes
- Using the CMP for monitoring kidney function is important in those with (…)
- CMP is used commonly in management of what conditions?
- CMP is used in suspected acute kidney injury from what?
- chronic diseases that can harm kidney function
- diabetes, hypertension, kidney disease
- dehydration, medications
Using the CMP is important for monitoring the health of the liver in what conditions?
- alcohol abuse disorder
- viral hepatitis
- cirrhosis of liver
- medication side effects
- The CMP is used for measurement of electrolytes, especially (1) and (2)
- CMP can be helpful to evaluate what?
- sodium and potassium
- blood protein levels, such as albumin (is the kidney spilling albumin into the urine)
What are the different monitoring parameters of the CMP?
- electrolyte function and abnormalities (sodium, potassium, chloride, CO2, anion gap, calcium)
- renal function (BUN and creatinine)
- liver function (bilirubin, alkaline phosphatase, AST, ALT)
- proteins (albumin, total protein)
- glucose monitoring (Diabetes)
What are frequent reasons to order a CMP?
- evaluation of abdominal pain to check for elevated liver enzymes, renal dysfunction
- evaluate for abnormalities of glucose levels in diabetes
- evaluate potassium/renal function in treatment of hypertension
- evaluate for liver dysfunction/liver toxicities with medication
- part of complete wellness physical
- What is the normal range of sodium?
- What is the normal range of potassium?
- What is the normal range of glucose?
- What is the normal range of BUN?
- What is the normal range of creatinine?
- 135-145 mEg/L
- 3.5-5.0 mEg/L
- 70-110 mg/dL
- 8-23 m mg/dL
- 0.7-1.3 mg/dL (males); 0.6-1.1 mg/dL (females)
- What is predominant in intracellular fluid?
- What is predominant in extracellular fluid (intravascular + interstitial)?
- potassium
- sodium
What is the predominant cation in the ECF and is a major determinant of ECF osmolality?
Na (sodium)
ECF osmolality (concentration of solutes) is the major determinant that controls (…)
sodium regulation
What are drivers of sodium homeostasis?
- free water and sodium excretion by the kidneys (most important)
- dietary sodium intake
What is the process of sodium regulation?
- receptors in the carotids, kidneys, or hypothalamus sense changes in sodium tonicity
- action is triggered
- When sodium levels are low, what happens?
- When sodium levels are high, what happens?
- aldosterone decreases sodium loss in the kidneys
- natriuretic hormone (the “sodium diuretic”) increases sodium loss in the kidneys
- What is also important in sodium regulation that is also known as vasopressin?
- Where is this produced and released by?
- What does this control?
- antidiuretic hormone (ADH)
- produced in hypothalamus and released by pituitary
- controls water “levels” that affect sodium level by dilution
When ADH is secreted, what happens?
- there is an increase in renal free water reabsorption
(as more water is reabsorbed, sodium is diluted and sodium concentration decreases)
What is the sodium regulation by ADH when plasma water inceases?
- plasma water increases
- sodium and osmolality decreases (by dilution)
- ADH secretion decreases
- collecting renal tubule becomes impermeable to water so water is not reabsorbed which increases need for urination
Decreasing ADH increases what?
urination (diuresis)
What is the sodium regulation by ADH when plasma water decreases?
- plasma water decreases
- sodium and osmolality increase
- ADH secretion increases
- collecting renal tubules reabsorbs more water, decreasing urination
Increasing ADH decreases what?
- diuresis (anti-diuretic hormone)
What are causes of hyponatremia (low sodium)?
- GI losses
- renal disease
- medications
- dietary sodium intake
- In hyponatremia, what is included in GI losses?
- What are you losing?
- How can this be corrected?
- vomiting, diarrhea
- losing sodium and fluids
- IV hydration (0.9% normal saline fluids)
- In hyponatremia, renal disease can lead to alterations in mechanisms for what?
- This results in what?
- water and sodium homeostasis
- impairment of free water excretion in kidneys, so water is retained, resulting in dilution of sodium
What medications usually cause hyponatremia?
mediations that treat hypertension
- thiazide diuretics named hydrochlorothiazide and Chlorthalidone
What is probably one of the most common reasons hyponatremia is seen?
medication use (hypertension meds)
In most cases, hyponatremia would only be seen in (…) dietary changes of reduced sodium
extreme dietary changes
Hypernatremia can result from what?
- increased sodium intake
- increased water loss in some cases but body releases ADH and thirst in response
- Usually, hypernatremia occurs in (…) water loss
- Which individuals do you see this in?
- unreplaced water loss
- elderly pts (if impaired mental faculties; may have diminished thirst stimulation; unable to access water after a fall)
- pts not given free access to water
- hypertonic saline solutions
- salt tablet ingestion
What diseases cause excessive water diuresis, concentrating the sodium, resulting in hypernatremia?
- diabetes insipidus (impaired ADH secretion = more dilute, watery urine)
What is the major intracellular cation? What percentage is intracellular?
- potassium
- 98%
Dietary intake of potassium should be relatively equal with (…)
potassium excretion
- What excretes 90-95% of potassium?
- What excretes the remaining 5-10%?
- kidneys
- colon
- What is the intracellular concentration of potassium?
- What is the value for plasma potassium concentraion?
- 150 mEq/L
- 4 mEq/L
Large amounts of potassium is intracellular, the (1) especially, but also cells of the (2), (3), and (4)
- myocytes
- liver
- bone
- erythrocytes
- If you eat a heavy potassium load, your body works to move most of that potassium into the (…)
- Even if 1% of intracellular potassium is shuffled to plasma, it can cause (…)
- cells
- dynamic increase in serum potassium to dangerous levels
Both hypokalemia and hyperkalemia can cause (…) due to its effects on (…)
- cardiac arrest
- cardiac muscle contractility
Simply moving your forearm during venipuncture can cause release of (1) and (2) results (false reading)
- potassium
- increase
What can lead to hypokalemia?
- diuretics used in hypertension (hydrochlorothiazide and chlorthalidone)
- decreased dietary intake of potassium
- diarrhea that results in loss of potassium
What can lead to hyperkalemia?
- ACE inhibitors used in hypertension (the “prils”)
- increased dietary intake of potassium
- crush injuries in which potassium is spilled from intracellular compartments into plasma
- What is one of the more important values on a CMP used to identify individuals at risk of diabetes or affected by diabetes?
- How can you check this value?
- glucose level
- capillary blood or whole blood
Glucose levels are a direct result of feedback mechanisms and are controlled by (1) and (2)
- glucagon
- insulin
(…) levels rise after eating, then cells in the Islet of Langerhans in the pancreas secrete (…) to decrease those levels
- glucose
- insulin
What leads to hypoglycemia?
- insulin or oral anti-diabetic medication overdose
- starvation
- insulin-secreting tumors (insulinoma)
What leads to hyperglycemia?
- diabetes
- stress
- pancreatitis
- oral corticosteroids (such as prednisone)
What is the function of the kidney?
maintain homeostatic balance of fluids, acid/bases, and electrolytes, conserve metabolic products, excrete wastes and produce hormones
What is the main filtering structure of the kidney?
the glomerulus
What is the number of milliliters of body fluid cleared by the kidneys per unit of time (mL/min)?
glomerular filtration rate
- Formation of what occurs primarily in the liver due to catabolism of protein into amino acids?
- What is formed in this process?
- What then combine to form urea?
- What is urea filtered by?
- urea
- ammonia
- ammonia molecules combine
- glomerulus
Approximately how much of urea is reabsorbed in renal tubules and the rest is excreted in urine?
50%
What does BUN (blood urea nitrogen) reflect?
the metabolic functioning of the liver and the excretory function of the kidneys
What leads to increased BUN?
- high protein diets
- GI bleeding
- dehydration
- renal failure
What leads to decreased BUN?
- low protein diets or starvation
- liver failure
- overhydration
- What is a very common cause of an increased BUN?
- What is a very common cause of a decreased BUN?
- dehydration
- overhydration
Any condition that results in low blood flow (volume) leads to increased reabsorption of BUN in the proximal convoluted tubule of the kidney, leading to (…)
increased BUN levels
Increased fluids and higher flow through the glomerulus results in decreases reabsorption of BUN, leading to (…)
decreased BUN levels
If a pt looks healthy and eats normal but has a low BUN, what is probably happening?
pt is probably drinking a lot of water
What values are renal function studies?
BUN and creatinine
- What is creatinine a byproduct of?
- What is it filtered by?
- Creatinine is secreted by the kidneys at what type of rate?
- Is creatinine metabolized/reabsorbed?
- What is creatinine excreted by?
- catabolism of creatine phosphate
- glomerulus
- constant rate
- no, not metabolized or reabsorbed
- excreted entirely by the kidneys
What is a better marker for kidney function? Why?
- creatinine
- it is excreted entirely by the kidneys and not affected by liver function
Creatinine levels are constant in what?
- absence of disease
- stable muscle mass
- consistent dietary intake (diets high in meat can increase serum creatinine)
- Production of creatinine is dependent of what?
- Children tend to have what type of creatinine compared to adults as a result?
- muscle mass
- lower creatinine
Increases in creatinine tend to occur (…) in renal disease because some of the creatinine is (…) by the renal tubules (10-20%)?
- later in renal disease
- secreted
A doubling is serum creatine generally reflects a (…) in the glomerular filtration rate
50% decrease in GFR
What leads to increased creatinine levels?
disorders of renal function, acute or chronic kidney injury:
- diabetic renal disease
- medication-induced
- dehydration or sepsis
- urinary tract obstruction (stone/tumor)
What is the number one reason for increased creatinine?
diabetic renal disease
What leads to decreased creatinine levels?
- debilitation (small, fragile)
- decreased muscle mass/frailty
What calculation is not included in the CMP but can be manually calculated?
BUN/Creatinine ratio
If both the BUN and creatinine are normal, is it necessary to calculate the BUN/creatinine ratio?
no - normal is normal
What refers to an increase in nitrogen containing compounds in the blood? What are the different types?
azotemia:
- pre-renal
- intra-renal
- post-renal
- What results from abnormalities in systemic circulation that decrease blood flow to the kidney? (before blood gets to kidneys)
- What results from abnormalities within the kidneys themselves? (structural)
- What results from obstruction of collecting system of the kidneys? (outflow)
- pre-renal azotemia
- intra-renal azotemia
- post-renal azotemia
What is the normal BUN/creatinine ratio?
10:1-20:1
What can cause pre-renal azotemia?
- volume depletion of any cause (dehydration)
- sepsis
- hypotension
- congestive heart failure
What can cause intra-renal azotemia?
- any of the main diseases that affect the structure of the kidneys (PKD)
What can cause post-renal azotemia?
- urinary tract obstruction
- nephrolithiasis
- prostatic hyperplasia
- tumors obstructing urine outflow
- What is the BUN/Cr ratio is pre-renal azotemia?
- What is the BUN/Cr ratio in intra-renal azotemia?
- What is the BUN/Cr ratio in post-renal azotemia?
- greater than/equal to 20:1
- less than/equal to 10:1
post-renal: - early: greater than/equal to 20:1
- late: less than/equal to 10:1
- Is calcium more abundant in ECF or ICF?
- What is calcium involved in?
- more abundant in ECF
- muscle contraction, cardiac function, neural transmission. clotting cascade
Calcium exists in the body in three forms, what are they?
- protein bound (mostly albumin)
- complexed (w/ phosphate, citrate, bicarb, sulfate)
- ionized (free calcium in its active form)
What are calcium levels regulated by?
parathyroid hormone (PTH)
- What is the parathyroid hormone (PTH) secreted by?
- Where are they located?
- parathyroid gland
- located on thyroid gland and calcitonin by thyroid itself
What happens when calcium levels decrease?
- PTH is released
- calcium is reabsorbed by kidneys, released from bone
- absorption from GI tract is increased
What happens when calcium levels increase too much?
calcitonin is released (it “tones it down”)
What is the most common cause of hypercalcemia?
hyperparathyroidism (producing too much PTH will make calcium keep being absorbed)
If pt has elevated calcium, what additional tests should you order and why?
- ionized calcium=unaffected by albumin protein levels
- PTH=check for hyperthyroidism
If you cannot identify a problem with the parathyroid hormone in pts with hypercalcemia, what should you think and why?
- malignancy
- its the second most common cause of hypercalcemia
- When thinking about bone metastasis, what is released from the bone when tumor invades it?
- What can produce PTH-like substances leading to hypercalcemia?
- calcium
- cancer (lung, renal, and breast cancer)
What leads to increased calcium levels?
- hyperparathyroidism
- solid tumors (w/metastases to the bones)
- parathyroid hormone-related protein secreting tumors (lung, esophagus, head/neck, cervical, and ovarian cancers)
What leads to decreased calcium levels?
- hypothyroidism
- hypoalbuminemia (low protein)
- vitamin D deficiency (vitamin D helps body better absorb calcium)
- What is formed from the breakdown of RBCs?
- When RBCs are broken down, they form what?
- Where does this mostly occur?
- bilirubin
- heme + globin molecules
- spleen
After heme is catabolized and bilirubin is formed, what is it called before it gets to the liver?
unconjugated bilirubin
Once in the liver, bilirubin becomes conjugated with glucuronide to become (…)
conjugated bilirubin
Because bilirubin is conjugated in the liver, what is it a good measure of?
liver function
To find the cause of elevated bilirubin, what must you do?
- ask for measure of direct (conjugated) and indirect (unconjugated) bilirubin as part of total bilirubin
- total bilirubin = direct + indirect (conjugated + unconjugated)
- Depending on where the defect occurs in the bilirubin pathway (direct or indirect), what can result?
- What can result if defect occurs prior to conjugation with glucuronide?
- hyperbilirubinemia
- unconjugated hyperbilirubinemia
- Jaundice occurs when bilirubin levels are (…)
- Jaundice can occur when total serum bilirubin exceeds (…)
- In newborns, liver may not have adequate levels of conjugating enzymes, so bilirubin remains (…)
- Unconjugated bilirubin has ability to pass through BBB and if levels are too high, what can result?
- Newborns with neonatal jaundice is placed under (…) which helps convert bilirubin to water soluble form
- too high
- 2.5 mg/dL
- unconjugated
- severe intellectual disability, encephalopathy
- bili light
What are causes of indirect (unconjugated) hyperbilirubinemia?
liver is the problem
- hepatocellular dysfunction:
*hepatitis
*cirrhosis
*neonatal hyperbilirubinemia
- any disease process that increases RBC destruction
*transfusion reaction
*sickle cell anemia
*hemolytic anemia (snakes)
What are causes of direct (conjugated) hyperbilirubinemia?
liver conjugates well, but structure or mass blocks outflow of bile to intestines
- gallstones
- obstruction of extrahepatic ducts by tumor
- liver metastases (obstruction)
- What is the normal % of indirect bilirubin in total bilirubin?
- What is the normal % of direct bilirubin in total bilirubin?
- 70-85%
- 15-30%
- When will indirect bilirubin be >85% of total bilirubin?
- When will direct bilirubin be >50% of total bilirubin?
- liver injury (alcohol, meds, hepatitis); RBC hemolysis
- obstructive cases (gallstones, tumors, obstructions)
What reflects the synthesis and maintenance of total amount of protein in the circulation?
serum protein
Almost all serum proteins are synthesized in the (…), therefore, failure of this organ can impair protein synthesis
- liver
What are the main components of the serum proteins?
- albumins (most abundant - 60%)
- globulins ( a1, a2, b, and gamma)
What causes a decrease in serum proteins?
malnutrition
- In healthy kidney tissue, most filtered protein in reabsorbed by the (…)
- In renal disease, the glomerulus becomes less able to filter proteins and overwhelms the ability of the renal tubules resulting in (…)
- Therefore, pts with low serum protein should have (…) to check for protein in the urine
- renal tubules
- loss of protein in urine
- urinalysis
What leads to hypoproteinemia (low serum protein)?
- hepatic failure or disease
- malnutrition or malabsorption
- renal disease or injury resulting in protein being spilled into urine
What leads to hyperproteinemia (high serum protein)?
- dehydration resulting in increased conc. of proteins due to less water
- some malignant states produce increased Igs
- infection resulting in increase in Igs
What is an important regulator of osmotic balance between intravascular and interstitial spaces (‘pulls’ water into circulatory system)?
albumin
What does albumin act as a transporter for?
- drugs
- bilirubin
- calcium
- thyroid hormones
- other hormones/enzymes
What type of half-life does albumin have?
- relatively long
- 12-18 days
- not always a good indicator of chronic liver disease/nutrition
- What impairs the kidneys ability to reabsorb albumin?
- What does this lead to?
- diseases that cause damage to the kidneys
- increased albumin in the urine
What are three liver enzyme/function tests on the CMP?
- alkaline phosphatase (ALP)
- aspartate aminotransferase (AST)
- alanine aminotransferase (ALT)
What can liver function test abnormalities be caused by?
- injury to hepatocytes from alcohol
- medications or toxicity
- fatty deposits in the liver
- viruses, such as hepatitis
Where are the highest concentrations of alkaline phosphatase?
- liver
- biliary tract
- bone
What liver enzyme is an enzyme that is widely distributed throughout the body in many tissues and also functions in growth and development of bones and teeth?
alkaline phosphatase
What liver enzyme is essential for bone mineralization?
alkaline phosphatase
- Alkaline phosphatase is present in what cells?
- What is it secreted into?
- present in Kupffer cells of the liver and biliary tract
- secreted into the bile
What increases alkaline phosphatase? (liver diseases)
- cirrhosis or tumors of liver
- drugs that are toxic to the liver
- obstruction of the biliary tract
What decreases alkaline phosphatase? (liver diseases)
- malnutrition states
Because ALP (alkaline phosphatase) is essential in new bone growth, it is elevated in any condition of what?
of bone formation (normal or pathologic)
What elevates ALP (alkaline phosphatase)? (bony disorders)
- cancers that metastasize to the bone
- primary cancer of the bone
- post-fracture
- hyperparathyroidism
- growing children
What is another liver enzyme used in the evaluation of the patient’s liver function that is found in highly metabolic tissue?
aspartate aminotransferase (AST)
Where is the AST enzyme found (aspartate aminotransferase)?
- What can increase release of AST into circulation?
- Why is it difficult to find where this increase is coming from?
- heart, liver, skeletal muscle
- any injury or cellular damage in the heart, liver, or skeletal muscles
- it is found in many places, not just one specific area
How high can AST levels rise (aspartate aminotransferase)?
high, up to 20x their normal value
What conditions elevate AST (aspartate aminotransferase)?
- liver disease, such as hepatitis (virus, toxin)
- tumors involving the liver
- infectious mononucleosis
- skeletal muscle disease or trauma (burns, myositis, muscular dystrophy)
What is a liver enzyme is found primarily in the liver but can be found in smaller amounts in other tissue (heart, skeletal muscle)?
alanine aminotransferase (ALT)
If liver damage occurs (…) is released into circulation
ALT
- If ALT is increased, what should you think?
- This enzyme tests is more specific for what than AST and ALP?
- liver abnormality
- more specific for liver disease
What conditions increase ALT?
- myositis (mild increase)
- MI (mild increase)
- hepatotoxic drugs (moderate increase)
- cirrhosis (moderate increase)
- hepatitis (major increase)
- We tend to think AST and ALT have a normal value around the 40s so if a patient that has a (…) elevation may or may not be significant
- If you have (…) than normal, it is frequently significant
- 2-3x elevated
- greater than 3x the normal
When you have elevated AST and ALT, what should you think?
- obesity and fatty liver
- alcohol and cirrhosis
- toxicity (medication: Tylenol)
- illness or injury to liver
A patient will have an AST:ALT ratio greater than 1 in what conditions?
- alcohol cirrhosis (frequently greater than 2)
- metastatic tumor of the liver
A patient with have an AST:ALT ratio less than 1 in what conditions?
- viral hepatitis
- mononucleosis
What does GGT stand for?
gamma-glutamyl transpeptidase
- Where is GGT present?
- Where is it not expressed?
- What is it involved in?
- kidneys, pancreas, liver, spleen, heart, brain, seminal vesicles
- not expressed in bone
- involved in amino acid transport
What can elevated alkaline phosphatase indicate?
both bone or liver disease
If alkaline phosphatase is elevated, what can you use to differentiate between bone or liver disease?
- the GGT
What should you do if you have an elevated alkaline phosphatase of unknown cause?
order GGT
- if elevated: look at liver as source of elevated ALP
- the liver and kidneys are major sources of GGT
What are major sources of GGT?
- liver
- kidneys
What can increase GGT?
liver disease:
- hepatitis
- cirrhosis
- alcoholic liver disease
- liver cancer/metastasis
- What does the BMP include?
- What does the BMP not include?
- 4-5 electrolytes (Na, Ca, K, CO2, Cl)
- 2 tests of kidney function (BUN and Creatinine)
- 1 test of glucose
- does not include liver function tests
If you only need to know the renal hydration status of your pt and are not concerned over their liver, what can you order?
BMP
In situations where the provider only needs to evaluate the functioning of the liver, what can you order?
LFTs
What do LFTs?
- total protein and albumin
- total bilirubin
- direct bilirubin
- ALT
- AST
- alkaline phosphatase
- GGT
What are indicated for LFTs?
- jaundice
- dark urine
- screening for hepatitis, hemochromatosis, other diseases that affect liver
- abnormal pain of unknown etiology
- monitoring for med side effects
- known liver disease
- alcohol abuse
- acetaminophen overuse
