Lab Testing Flashcards
Sensitivity
Ability of test to give positive result when what entity is present
Specificity
Ability of test to give negative result if entity tested not present (lack of false positives)
Positive predictive value
Ratio of pts truly truly diagnosed as positive test results. Ratio shows how likely it is to get a true positive
Negative predictive value
Ratio of pts who do not have disease compared to those that tested negative
What is tested in CBC
Hemoglobin
Hematocrit
RBC
RBC indicies (mean corpuscular volume, hgb, hgb concentration)
RBC width
WBC differential
Platelet count
Hemoglobin makeup
mostly 2alpha and 2 beta chains
4 globin
4 heme
Iron in heme for O2 transportation
Hematocrit
Ratio of red cell volume to whole blood.
Expressed as percentage.
Indirect measure of RBC number and volume.
Found using centrifuge.
Rule of three
3 x hgb = hct
hgb/3 = rbc
RBC indicies
Mean corpuscular volume
Mean corpuscular hemoglobin
Mean corpuscular hemoglobin concentration
Mean corpuscular volume
Average volume of a cell.
MCV = hct x 10
Normocitic = 80-100
Anemia with low corpuscular volume cause
Iron deficeincy
Lead poisoning
Chronic
Anemia with normal mean corpuscular volume cause
Bleeding
Hemolysis
Marrow failure
From renal or liver disease
Anemia with high mean corpuscular volume
B12 deficiency
Folate deficiency
Drugs
Mean cell hemoglobin concentration
Measure of avg concentration or percentage of hemoglobin in single rbc
Hgbx100/hct
RBC distribution width (RDW)
Shows variation in RBC size
Useful in classifying anemia
Normal WBC count
4000-11000
Leukocytosis
High WBC
Leukopenia
Low WBC
Bacterial infection WBC
Increased neutrophils
Viral infection WBC
Increased lymphocytes
Allergies/parasites WBC
Increased eosinophils
TB WBC
Increased monocytes
Neutrophils
Most abundant granulocyte
3 lobed nucleus
Phagocytic
Bacterial infection
Band
Immature neutrophil
Lymphocytes
Second most abundant WBC
T and B cells
Chronic bacterial infections
Viral infections
Eosinophils
Bilobed nucleus
Release cytokines and histamine in allergic response, parasitic infection, and drug interactions
NO response in bacterial or virals
Phagocytic
Basophils (mast cells)
Allergic reaction
Phagocytic
IgE initiate degranulation
Monocyte
Largest WBC
Phagocytic
Removes debris
Left shift
Increase in bands (immature neutrophils)
Associated with bacterial process or tissue necrosis.
Thrombocytosis
High platelets
Thrombocytopenia
Low platelets
Reticulocyte
Immature RBC
Erythrocyte Sedimentation Rate (ESR)
Rate red cells settle out from plasma
Elevated in inflammation
C-reactive protein
Acute phase recant protein used to show inflammation
Aldosterone
Stimulates kidneys to reabsorb Na
Raises Na
Lowers K
Natriuretic hormone
Increases renal loss of Na
Lowers Na
Antidiuretic hormone (ADH)
Makes kidney reabsorb water in kidneys.
Raises Na
regular Na level
135-145
Hypernatremic
High Na
Hyponatremic
Low Na
Potassium
Important in electrical potential especially in muscle.
No reabsorption from kidneys so must be in diet regularly.
Minor changes are big deal
K normal range
3.5-5
Hyperkalemic
High potassium
Hypokalemic
Low potassium
Chloride
Follows Na to balance charge.
Normal Cl
95-105
Bicarbonate
Measure of CO2 in blood
Venous blood not that accurate
Normal bicarbonate
22-30
Blood urea nitrogen (BUN)
Measurement of renal function and glomelular filtration rate.
Measurement of liver function.
Urea formed in liver from metabolism then kidney filters
Effected by protein intake and hydration
Normal BUN
7-20
Creatinine
Directly proportional to kidney function.
Nothing to do with liver
Skeletal muscle biproduct
Normal creatininie
0.6-1.2
Normal glucose level
70-100
Normal Ca
8.5-10.2
Hypercalcemia
High calcium
Hypocalcemia
Low calcium
Comprehensive metabolic panel (CMP)
Albumin
Total protein
ALP
ALT
AST
Bilirubin
Albumin
Help with osmotic pressure (keeps fluid in vessels)
Can be measured to check liver function
Globulin
Non-albumin proteins.
Total protein
Albumin + globulin in serum
Alkaline phosphatase
Found in liver, biliary tract, epithelium, bone.
In kipffer cellls.
Raised when there is damage to liver or bone.
Alanine aminotransferase (ALP or SGPT)
In liver.
Elevation causes release of hepatocellular enzyme into blood.
Aspartate aminotransferase (AST)
Found in liver.
Amount of AST elevation shows number of cells affected by injury or disease
AST/ALT ratio
greater than one shows alcoholic cirrhosis, liver congestion, lliver tumor.
Less than one shows hepatitis or mononucleosis
Bilirubin
In bile.
Measured to find jaundice
Specific gravity
Measure of concentration of urine.
Higher means less hydrated
What if found in urine indicates UTI
Leukocytes
Nitrite
Ketone in urine
Inadequate carb intake
Starvation
Severe exercise
Vomitine
Bilirubin in urine
Suggests disease affecting bilirubin metabolism after conjugation or defects in excretion
