Flashcards in EXAM2_WORKSHOP2_Serum_Chemistry_Profile Deck (15)
three classes based on solubility in saline:
Plasma Serum protein (most abundant)
-Made in Liver
HL ~16 days
12g/day (25% hepatic protein synthesis)
1. oncotic pressure
2. maintains plasma volume (fluid between tissue & IS)
3. Carrier protein (FA or Ca)
-can also act as reservoir
Important notes of Serum chemistry profile
1. not used to make a diagnosis
2. best if used over a long time (months, years) to follow patients response to treatment
3. helps support ideas from history and physical exam
If analyte follows Gaussian Distribution:
Analyte values use the MEAN +- 2 SD.
-2.5% healthy will have values above these limits
-2.5% healthy will have values below these limits
If analyte follows Skewed (non-Gaussian) distribution:
Values for a sample population ranked by numerical value and references are established by dropping the highest 2.5% and lowest 2.5% of the falues
Critical Difference (CD)
What is it?
Why is it important?
Determines if differences between two values in a patient are statistically significant
-Smallest variability (low CD coefficients %)
(Na, Cl, Ca, Proteins, Albumin)
-Intermediate variability (Glucose, cholesterol, phosphate)
-Large Variability (highest CD coefficient %)
(uric acid, urea, enzymes, Triglycerides)
Calculate Critical Difference:
IF |a-b| > CD*(a+b)/2 then the difference is statistically significant
6 Examples of molecules that albumin transports in the blood
What is it?
What is it proportional to?
how much attributed to albumin?
-force that pulls water back into the capillaries to maintain normal blood volume
OP proportional to concentration of protein molecules in blood
-80% of oncotic pressure caused by Albumin
20% by globulins
Hypoalbuminemia (what albumin shift?)
body shifts albumin from Interstitial fluid to vascular system
Edema results in net fluid accumulation in interstitium
Hydrostatic pressure in blood - oncotic pressure (back into blood)= filtration pressure
- have low net outflow (on arterial side)
Absorbing Pressure (AP)
Hydrostatic pressure in vein- oncotic pressure in Interstitial space= AP
HP>OP = net outflow in artery
What happens when albumin is low?
Low oncotic pressure (hard to get fluid back into vein)
-FP is increased and more fluid moves out into interstitium
Filtration "out" pressure is greater than absorption "in" pressure (respective of blood volume)
RESULTS IN EDEMA
Albumin bound calcium: When does it decrease?
Free Ca (bioavailable ca)
Do Free Ca levels vary? what if albumin-Ca varies?
Total serum Ca = (albumin bound Ca + free Ca)
Albumin-bound Ca: can decrease when albumin low, or affinity changes (acidosis)
Free "bioavailable" calcium in plasma is tightly regulated and remains constant regardless of albumin-bound Ca
Acidosis affects what Ca levels?
Acidosis decreases albumin binding Ca and Overall Ca levels but not the bio-available Ca levels (stay constant)