1-6 Basic Lab Data Flashcards
Specificity
A measure of how well a test detects a disease without yielding a false + result. The probability that a test will be negative in the absence of a disease.
How accurately the test identifies people who DO NOT have a disease.
What does a 100% specific test mean?
A 100% specific test only results in a positive result when the condition is present in the patient.
Sensitivity
A measure of how well a test detects a disease without yielding a false negative result. The probability that the test will be sensitive in the presence of a disease.
How accurately the test identifies people who DO have a disease.
What does a 100% sensitive test mean?
A 100% sensitive test reveals all patients with the tested-for condition. No test is 100% sensitive.
Normal pH range
7.35-7.45
Normal PaCO2 range
35-45
Normal HCO3 range
22-26
What are the main acid excreting organs?
Lungs and Kidneys
What is the peak increase of PCO2? And why?
- An end tital of 55 COULD be what the patient needs. If it gets over that, it becomes officially not good and we need to do something about it.
What is the primary imbalance in a respiratory acidosis and alkalosis
CO2
What is the primary imbalance in a metabolic acidosis or alkalosis
HCO3
Base excess range
-3 - +3
PaO2 Range
80-100 mmHg
SaO2 Range
90-100 %
What does the PaCO2 tell us?
ventilatory status
What is base excess/deficit?
The amount of base or acid required to titrate the pH of one liter of blood to normal pH. Used for METABOLIC acid/base disorders.
What does a negative base deficit mean? What does a positive base excess mean?
Negative base deficit: indicates the patient has a metabolic acidosis
Positive base excess: indicates the patient has a metabolic acidosis.
What happens when base excess goes above +3 or below -3?
The patient becomes more unstable. BE x 10 = the % failure of the pt’s current care.
Understand the difference between PaO2 and SaO2.
PaO2- the partial pressure of oxygen dissolved in the blood (if this value is less than 60, the pt WILL desat when the vent is disconnected)
SaO2- how much oxygen is bound to hemoglobin
For every 10 mmHg change in PCO2
the pH will change 0.08 in the opposite direction
For every 10 mEq change in HCO3
the pH will change 0.15 in the same direction
What causes a high O2 affinity?
LOW- O2, CO2, 2,3-DPG, temp
HIGH- pH
What does a CBC consist of?
WBC
WBC differential
RBC
Hgb
Hct
Platelet count
What does a left shift in neutrophils indicate and why?
A left shift is seen as an increase in the number of bands and is common in infections.
immature neutrophils = active infection (which produces a left shift)
A catecholamine dump is associated with an increase in what type of WBC?
Eosinophils
What type of WBC causes pyrogenesis?
Monocytes
What are the two types of lymphocytes, what response do they typically mitigate, and where do they mature?
B-type mature in the bone marrow, deal with bacterial.
T-type mature in the thymus and deal with tumors or viruses.
What does the hematocrit measure?
the volume of RBCs found in 100 mL of blood and expressed as a percentage.
Less than what platelet count is associated with risk of bleeding?
150,000
Normal sodium range
135-145
Where will the fluid go if there is elevated vs low Na
Low Na = fluid will move from the blood into the tissues.
High Na = fluid is drawn out of the tissues and moves into the blood. High risk of spontaneous head bleeds with this one.
Normal K+ value
3.5-5
What should you suspect if you see a sine wave on the ekg?
“v-tach” at less than 120 is most likely hyperkalemia
What is the relationship between K+ and pH?
Inverse.
acidic patient = k+ comes out of the cell
basic patient = potassium is pushed into the cell
What is the threshold for treating hypoglycemia in neonates and infants/children
Neonates: < 40
Infants: < 60
BUN is a metabolic by-product from the breakdown of what?
blood, muscle, protein
Tell me about the sensitivity and specificity of BUN for kidney failure
high sensitivity and lower specificity
Creatinine is a metabolic by-product from the breakdown of what?
protein
Tell me about the sensitivity and specificity of creatinine for kidney failure
high specificity and lower sensitivity
What is albumin and what does it do?
Albumin is a plasma protein made by the liver.
Water follows albumin, so it regulates osmotic pressure (fluid balance).
Elevated liver enzymes indicate ______
liver damage/infection
How is bilirubin created and what does a high level indicate?
bilirubin is created when RBCs are broken down and recycled. A high level can indicate hemolytic anemia, liver damage, blockage of the portal vein, or gallbladder disease.
The liver converts ammonia to what?
urea
What is the most common reason for elevated lactic acid levels?
Sepsis
What does a high serum osmolarity mean?
What does a low serum osmolarity mean?
high means that the blood is very concentrated, so fluid will be shifting from the tissues and into the blood.
low means that the blood is very dilute and fluid will be shifting from the blood and into the tissues.
Prothrombin time (PT) measures the efficacy of ______
coumadin-type anticoagulants
Partial thromboplastin time (PTT) measures the efficacy of ______
intrinsic clotting factors, HEPARIN
International normalized ratio (INR) compares ____
How do you interpret the value?
the patient : standardized control
If a person is not on coagulation therapy, the patient and control will be the same, resulting in an INR of 1.
What should the INR be for a patient who is receiving warfarin therapy?
2-3
What does a high vs normal D-dimer mean?
High = pt is making extra clots (DVTs, PEs)
Normal = pt is not making extra clots
What is the most specific blood test for an acute MI
Cardiac-specific troponin (normal value 0.0 - < 0.50 mg/mL
What is the hormone produced by the ventricles when they are stretched? What can it indicate?
B-type natriuretic peptide (BNP). High levels can indicate CHF (LV) or PE (RV).
What is the order UMBC wants us to interpret ABGs?
- check the pH
- check the PaCO2
- check HCO3
- is it ROme or roME (resp or met)
- check PaO2
- check anion gap (when an acidosis)
How well the test can RULE OUT a condition
specificity
How well can the test FIND a condition
sensitivity
Which system acid/base abnormality is associated with changes in the base excess?
Metabolic
What are the conditions that can cause a left shift in the oxyhemoglobin dissociation curve?
INCREASED AFFINITY FOR 02
decreased temp
decreased 2,3-DPG
decreased PCO2
decreased PCO2
increased pH
What are the conditions that can cause a right shift in the oxyhemoglobin dissociation curve?
DECREASED AFFINITY FOR 02
increased temp
increased 2,3-DPG
increased PCO2
increased PCO2
decreased pH
Are platelets low or high in DIC?
low
