Glossary of Clinical Lab: Chem panels

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Electrolyte panel consists of...
-calcium (sometimes)
Basic Metabolic panel consists of..
Renal function panel consists of...
Hepatic Function panel consists of..
-A/G ratio (albumin/globulin)
-bilirubin (direct and indirect)
-total protein
Lipid Panel consists of...
-cholesteral/HDL ratio
Comprehensive Metabolic panel consists of...
-A/G ratio
-total bilirubin
-globulin (calculated)
-protein (total)
hepatic panel (acte with reflex) consists of...
-Hep A antibody (IgM)
-Hep B surface antigen
-Hep C core antiobody (igM)
-Hep C antibody

reflex - if something is positive, the lab will automatically do further testing
Thyroid panel
-Free T4 (calculated)
Potassium is the major....
Importance of potassium...
-controls cellular osmotic pressure
-important to cellular metabolism
-activates enzymatic rxns
-helps regulate acid/base balance (H+ ions are substituted for sodium and potassium in the renal tubule)
-influence kidney filtration
-maintains neuromuscular excitability
Potassiun: normal range
3.5-5.3 mEq/L
Where is K+ Secreted ?
distale tubule
K+ is screted from the distal tubule at a rate dependent on...
-K+ intake
-presence of aldosterone
-availbaility of Na+ for reabsorption
-balance of H+ and K+
-acid base status
-tubular flow rate
How does aldosterone effect K+?
-under the influance of aldosterone, the kidneys conserve Na by wasting K+ (they exhange Na for K) even if both are in short supply
Hypokalemia results from...
-shifing K+ into cells
-k+ loss from GI tract
-renal excretion
-decreased intake
Causes of hypokalemia...
-renal diseasee
-potent loop diuretics (furosemide)
-loss of K+ (emesis, diarrhea, sweat)
-insulin (causes shift of K+ into cells)
Excessive hypokalemia may lead to...
-V fib
-other arrythmias (Torsades de pointes)
-respiratory paralysis
EKG changes with hypokalemia...
-ST depression
-flattened T wave
-U wave
-peaked P wave
Most common cuase of K+ defiency is...
(deficiency = normal/natural causes)
-GI loss
-inadequate intake
Most common cause of K+ depletion is..
(depletion = external cuase)
-IV fluids without adequate K+ supplementation
Hyperkalemia results from...
-K+ shift out of cells
-decreaed renal excretion
-excessive intake
Causes of hyperkalemia include...
-renal failure
-hemorrhagic shock
-addisons disease (hypoadrenalism)
-excessive IV supplementation
-massive cell damage (burns, crush injury)
-uncontrolled DM/decreased insulin
-tranfusion of large quantities of stored blood
Symptoms of hyperkalemia..
-intestinal colic
-muscle irritability
-flaccid paralysis
EKG changes with hyperkalemia...
-wide QRS
-flat P wave
-peaked T wave
-ST depression

-may lead to v-fib and cardiac arrest
Sodium is the major...
Importance of sodium..
-maintenance of water distrubitution!!!
(account for 90% of osmostically acive solute in plasma and intersitial fluid)
-maintenance of electric neutrality of serum
-important to cell physiology
What do sodium levels test?
-changes is water balance
(rather than changes in sodium balance)
Sodium levels are used to determine...
-electrolyte balance
-acid base balance
-water balance
-water intoxication (dec Na)
-dehydration (inc Na)
Sodium: normal values
Adult: 135-145 mEq/L
Sodium: Panic values
90-105 mEq/L - severe neurologic sx

<120 mEq/L - weakness, dehydration

>155 mEq/L - CV and renal sx

>160 heart failure
Machanisms for sodium regulation include..
-renal blood flow
-carbonic anhydrase enzyme activity
Where is sodium filtered, reabsorbed etc?
-Filtered at glomerulus
-reabsorbed at proximal tubule and Loop of Henle, then again at distal tubule if aldosterone is present
Rate of Na reabsorption depends on..
-level of K+
-balance of H+ and K+
-acid base status
-tubular flow rate
Hyponatremia is the ....
MOST COMMON electrolyte disorder!!
Hypnatremia is caused by..
-dueresis (sweating, vomiting, severe diarrhea, drugs)
-over hydration
-inappropriate ADH syndrome
-false hyponatremia (from IV)
-sever burns
-Addisons disease (impaired Na reaboroption)
-diabetic hyperosmolarity (excess glucose)
Hypernatremia is caused by...
-dehydration (dec water intake, exces water output, exciss skin output, excess GI output, high protein tube feeds)
-inability of kidneyy to conserve water (hyperaldosteronism, cushings dz, diabetes insipidis, solute diaresis (glucose, mannitol, urea))
Chloride: normal values
98-106 mEq/L
Cholride: critical values
<80 mEq/L

>115 mEq/L
Importance of cholride:
-maintains electrical neutrality (mainly as a salt with sodoium - follows sodium losses and accompanies sodium excess to maintain neutrality)
-serves as buffer to assist in acid/base balance
-gives indication of hydration status
-major extracellular ANION
Does hyper or hypo cholremia usually occur alone?
No, usually with a shift with sodium or bicarb
Sx of hypocholeremia:
-hyperexcitablity of nervouse system and muscles
-shallow breathing
Sx of hypercholeremia:
-deep breathing
Causes of hypercholeremia:
-excessive infusion of normal saline
-metabolic acidosis
-renal tubular acidosis
-Cushings syndrome
-kidney disfunction
-resp alkalosis
Casuses of hypochloremia:
-vomiting and prolonged gastric suction
-chronic resp acidosis
-metaboic alkalosis
Carbon dioxide: normals
adult/elderly: 23-30 mEq/L
Carbon dioxide: critical values
<6 mEq/L
What is actually measured to get CO2?
Indication for CO2 test?
-rough guide to acid/base balance
-evaluate pH
-assist in evaluating electrolyte status
What three things does Serum CO2 measure?
dissolved CO2

BUT H2CO3 and dissolved CO2 are very low so serum CO2 is a relection of HCO3 content
Role of HCO2?
-maintain electric neutrality along with choloride
HCO3 Increases in...
-metabolic alakalosis
-severe vomiting
-gastric suction
HCO3 decreases in...
-metabolic acidosis
-chonic diarhhea
-diabetic ketoacidosis
-chornic use of loop diueretics
-measures the number of dissolved particles in a solution (plasma)
osmolality normals:
Serum: 275-295 mOsm/kg H20

Urine: 300-900 mOsm/kg H20
Other signs and monitors of fluid status:
-vital signs (if no fluid, dec BP)
-JVD/venous filling
-skin turgor (dehydration dec resiliency)
-Input and output
-daily weight changes
-Blood ureas nitrogen
-final breakdown product of protein metabolism
-excreted at rate proportional to GFR
-used as gross index of GFR rate (inversly proportional)
-made in liver
BUN: normal
7-18 mg/dl

panic >100 mg/dl
causes of increased BUN (azotemia):
-rapid protein catabolism
-decreased kidney function
-impaired renal fcn d/t CHF, shock, salt/water depletion, acute MI, Urinary tract obstruction
Causes of decreased BUN:
-liver failure
-anabolic steroid use
-nephrotic syndrome
Causes of Pre-renal azotemia:
-excessive protein catabolism
Causes of post-renal azotemia:
-uretal or orethral pbstruction
Synthesis of urea depends on ...
liver (functional liver)

So liver disease causes dec BUN
Serum Creatinine
-final breadown product of creatine phosphate in msuscle
-daily generation of creatinine is constant and kidneys excrete it very well (virtually 100% first pass excretion)
Serum creatinine: normal
0.5-1.5 mg/dl

panic >10 mg/dl
Causes of increased creatinine:
-impaired renal function
-chornic nephritis
-Urinary tract obstruction
-muscel disease
-some drugs including cephalosporins
Causes of decreased creatinine:
-small stature
-decreased muscle mass
-advanced and sever liver disease
BUN:Creatinine ratio
normal 10:1 to 20:1

values anbove 20:1 suggest dehydration (give IV fluids)
Creatinine vs BUN
-BUN correlates better with symptoms of uremia than creatine levels
-BUN levels rise more rapidly and sharply
-Creatinine is a better indication of kidney function
-creatinine is more specific and more sensitive indicator of kidney dz than BUN
Role of Caclium
-nerve transmission
-excitability of cardiac/skeletal muscle
-skeletal growth
Where is calcium found?
99% in bone

1% serum

1/2 of serum calcium is bound to albumin, the other 1/2 is unionized (active)
What regulated Calcium levels?
-Parathyroid hormone
-vitamin D
-closely related to albumin levels
-closely tied to bone metabolism
Calcium: normal values
8.4 - 10.2 mg/dl
Calcium: panic values
<6 mg/dl (tetany, convulsions, seizures)

>13 mg/dl (cardiotoxicity, arrythmias, coma)
Causes of Hypocalcemia...
-vitamin D deficiency
-renal failure
-excess IV fluids may mimic hypocalcemia
Causes of Hypercalcemia...
-bone turnover
-metastatic CA
-multiple myelome
-primary bone tumors
Roles of Magnesium
-helps with neuromuscular tranmission and muscle contraction
-role in muscle relaxation
-protein synthesis
-enzyme activation
-oxidative phosphorylation
Where is magnesium found?
1-3% extracellular

rest is intracellular
Magnesium: normal values
1.2-2.6 mg/dl
Magnesium: panic values
<1 mg/dl (tetany)

5-10 mg/dl (CNS depression, n/v, fatigue)
10-15 mg/dl (EKG changes, respiratory paralysis)
>30 mg/sl (heart block, cardiac arrest)
What regulates magnesium?
-KIDNEY (serum concentration of Mg provides feedback inhibition so inc Mg, less absorption in loop of henle/distal tubules)
-absorption in small intestine
-excretion via glomerular filtration
-closely tied to calcium (Mg needed for absoprtion of Ca)

Causes of decreased magnesisum?
-decreased absorption (malabsoprtion, bowel resection)
-excessive elimination (alcoholism, malignancy, dieretics, prolonged NG suction, diabetic acidosis)
Sx of decreased magnesium?
-hyperactive reflees
-muscle tremors
Causes of increased magnesium?
-excessive intake or inadequte excretion
-renal failure
-anatacids with magnesium
Sx of increased magnesium?
-flaccid paralysis
-weak/absent DTRs
-slow weak pulse
-respiratory paralysis
-cardiac arrest
Where is Phosphate found?
85% is combined with calcium in bone
What is phohpate associated with?
INVERSELY related to calcium levels
What regulates phosphate?
parathyroid hormone
Causes for Hyperphosphatemia...
-kidney dysfcn
Causes for hypophosphatemia...
-liver disease
-acute alcoholism
Uric Acid
-formed from breakdown of necleic acids
-end product of purine metabolism
-produced in liver
-constantly produced bc purine turnover is constant
-2/3 excreted in urine; 1/3 excreted in stool
Uric acid: normal values
men 3-7 mg/sl
women 2.6-6.0 mg/dl
Causes of increaed uric acid
-increased dietary purines (organ meat, veggies, achovies)
-cytologic tx of malginancies (inc cell breakdown)
-renal failure
-alcohol intake
-multiple myeloma
-metastatic CA

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