Download Laboratory Tests

Labs
Laboratory Tests
• May include laboratory examinations of
patient’s:
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Blood
Urine
Cerebrospinal fluid (CSF)
Other body fluids
CCTP Responsibilities
• Understand or feel comfortable with:
– Normal ranges for each lab value
– Associated physiologic meaning of test
• Understand purpose of performing tests
– Not meant to satisfy curiosity
– Not meant to reassure concerned family or
staff
Chemistry Review
• Ions
– Cation: positively charged
– Anion: negatively charged
– Ionic bond: ions of opposite charges joined
together
– Mole: unit representing 6.02 x 1023 atoms
– Equivalents (Eq): measure amounts of
charged particles
Chemistry Review
• Osmolarity
– Osmotic pressure measured in humans
– Osmole (Osm): pressure created by 1 mole of
particles in solution
– Depends on number of particles in fluid, not
size of particles
• Concentration
– Amount of substance in given volume of fluid
Biochemistry Review
• The human body contains thousands of
different kinds of proteins.
• Enzymes
– Proteins that act as catalysts for biochemical
reactions
– Tests measure amount present
– Measured in units per liter (U/L)
Lab Values in Blood Samples
• Basic metabolic panel (or Chem-7)
• Sodium (Na+)
– Normal range: 135 to 145 mEq/L (mmol/L)
– Elevated: traumatic brain injuries
– Decreased (hyponatremia): congestive heart
failure, renal failure, liver disease, diuretic
therapy
Lab Values in Blood Samples
• Potassium (K+)
• Normal range: 3.5 to 5.0 mEq/L
• Elevated: cardiac abnormalities, atrial
arrest
• Decreased (hypokalemia): arrhythmias,
muscle pain, hyporeflexia, nausea,
vomiting, orthostatic hypotension
Lab Values in Blood Samples
• Chloride (Cl–)
– Normal range: 95 to 105 mEq/L
– Decreased (hypochloremia): renal dysfunction
– Elevated (hyperchloremia): numbness,
tingling, hyper-tonicity, decreased respiratory
rate, nervousness, signs of CNS stimulation
Lab Values in Blood Samples
• Carbon dioxide (CO2)
– Normal HCO3 value: 22 to 26 mEq/L
– Normal CO2 value: 21 to 32 mEq/L
– Decreased: May indicate metabolic acidosis,
respiratory alkalosis
– Elevated: Metabolic alkalosis, respiratory
acidosis
Lab Values in Blood Samples
• Blood urea nitrogen (BUN)
– Normal range: 8 to 23 mg/dL
– Elevated: May occur with decreased renal
function, high-protein diet, crush injuries,
burns
• Creatinine
– Normal: 0.6 to 1.2 mg/dL
– Elevated: May cause permanent kidney
damage
Lab Values in Blood Samples
• Total calcium
– Normal range: 8.5 to 10.5 mg/dL
– Decreased: Seen in renal insufficiency,
hypomagnesemia, hyperphosphatemia,
massive blood transfusion, decreased
parathyroid hormone states
– Elevated: Seen in hyperparathyroidism,
parathyroid secreting tumors
Lab Values in Blood Samples
• Glucose
– Normal range: 70 to 110 mg/dL
– Decreased: dizziness, unconsciousness
– Elevated: coma, death
• Ionized calcium
– Normal range: 4.60 to 5.08 mg/dL
– Decreased: cause serious arrhythmias
Lab Values in Blood Samples
• Magnesium (Mg)
– Normal range: 1.5 to 2.5 mEq/L
– Elevation caused by: renal defects, severe
dehydration, Mg, diabetic coma, aspiration of
sea water
– Decrease caused by: GI distress, vomiting and
diarrhea, cirrhosis, pancreatitis
Blood Components
• Complete blood count (CBC) test
• Hematocrit (Hct)
– Normal range: 41% to 50%
• Hemoglobin (Hg or Hb)
– Males: 135 to 175 g/L; females: 120 to 160 g/L
– Elevated: Hemoconcentration caused by
dehydration, burns, or excessive vomiting
– Decreased: Most types of anemia
Blood Components
• Carboxyhemoglobin (COHb)
– Normal levels: Not to exceed 0.02 (2%)
– Assessment used to diagnose carbon
monoxide poisoning
• Red blood cell (RBC) count
– Normal range: 3.9 to 5.5 X 106/μL
– Decreased: All types of anemias
Blood Components
• White blood cell (WBC) count
– Normal range: Between 5,000/μL and
10,000/μL
– Decreased: aplastic anemia, vitamin
deficiencies, sepsis
– Elevated: inflammation, infection,
malignancies, vascular conditions, steroid use,
stress from trauma
Blood Components
• Platelet count (Plt)
– Normal range: 150 to 400 X 103/μL
– Elevated: myeloproliferative disorders
– Decreased: thrombocytopenia, disseminated
intravascular coagulation, high levels of
platelet antibodies
Proteins
• Total protein
– Normal range: 6.0 to 8.0 g/dL
• Albumin
– Normal range: 3.5 to 5.0 g/dL
– Decreased: increased protein catabolism,
decreased production, edema in spaces
between cells and tissues; hypoalbuminemia
– Elevated: not pathologic
Proteins
• C-reactive protein (CRP)
– Normal range: 0.08 to 3.1 mg/L
– Elevated: May indicate significant
inflammatory disease
• Myoglobin
– Normal range: 19 to 92 μg/L
– Elevated: May indicate myocardial infarction
Proteins
• Lactate dehydrogenase (LDH)
– Normal range: 100 to 200 U/L
– Elevated: Ratio over 85% indicates possible
AMI, also helps diagnose pneumonia,
pancreatitis
• Creatine kinase (CK)
– Normal range: 40 to 150 U/L
– Elevated: Muscle damage, possibly related to
AMI
Proteins
• Troponin I
– Normal range: 0 to 0.04 ng/mL (for cTnI)
– Elevated: Indicate MI up to 7 days following
event
• B-type natriuretic peptide (BNP)
– Normal range: Less than 167 pg/mL
– Elevated: Indicates abnormal ventricular
function, congestive heart failure
Proteins
• Aspartate aminotransferase (AST)
– Normal range: 10 to 30 U/L
– Elevated: liver damage, alcoholic cirrhosis,
hepatitis, cancer
• Alanine aminotransferase (ALT)
– Normal range: 10 to 40 U/L
– Elevated: liver damage, alcoholic cirrhosis,
hepatitis, cancer
Proteins
• Total bilirubin
– Normal range: 0.3 to 1.2 mg/dL
– Elevated: liver disease, biliary tract
obstruction, RBC hemolysis
• Direct bilirubin
– Normal range (direct): 0.1 to 0.3 mg/dL
– Normal range (indirect): 0.2 to 0.9 mg/dL
Proteins
• Alkaline phosphatase
– Normal range: 30 to 120 U/L
• Amylase
– Normal range: 27 to 131 U/L
– Decreased: Seen in cystic fibrosis
• Lipase
– Normal range: 31 to 186 U/L
– Elevated: bile duct obstruction, biliary disease
Coagulation
• Prothrombin time (PT)
– Normal range: 10 to 13 seconds
– Elevated: liver disease, warfarin therapy
– Decreased: vitamin K deficiency, in DIC,
following massive transfusion
Coagulation
• Activated partial thromboplastin time
(aPTT)
– Normal range: 25 to 40 seconds
• International normalized ratio (INR)
– Normal range: 0.9 to 1.3
– Elevated: liver disease, warfarin therapy,
anticoagulant use
Other Lab Profiles
• Lactate
– Normal range: 5.0 to 15 mg/dL
– Elevated: inadequate perfusion, oxygenation
of cells, tissues, end organs
• Osmolality
– Normal range: 275 to 295 mOsm/kg
• Ethanol (EtOH)
– Elevated: Intoxication defined as more than 80
mg/dL
Other Lab Profiles
• Calculated values
– AST:ALT determines cause of liver
dysfunction
– BUN:Creatinine determines cause of
increased levels of these two metabolites
– Anion gap (AG): Increase indicates presence
of unmeasured anions (lactic acid)
Acid-Base Status
• Hydrogen ion concentration (pH)
– Normal range for arterial: 7.35 to 7.45
– Normal range for venous: 7.31 to 7.41
• Partial pressure of carbon dioxide
– Respiratory derangement present either above
or below normal range of 35 to 45 mm Hg
Acid-Base Status
• Bicarbonate
– Normal range: 22 to 26 mEq/L
– Derangement seen with acidosis- or alkalosisrelated conditions with metabolic aspect
• Base excess (BE)
– Normal range of –2 to +2
– Negative: Excess acid or lack of base
– Positive: Excess base or lack of acid
Oxygenation Status
• Partial pressure of oxygen
– Normal range: 80 to 100 mm Hg
– Decrease: Hypoxia at levels below 80 mm Hg
• Oxygen saturation
– Normal range: Greater than 95%
Blood Group Testing
• Four blood types result from two primary
antigens (A, B)
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Type A carries A antigen
Type B carries B antigen
Type AB carries A and B (universal recipient)
Type O carries neither A nor B (universal
donor)
Rh Antigen D (Rh Factor)
• Found in majority of the population (Rh
positive)
• May cause immune response reaction
when given to Rh negative patients
– Especially dangerous in Rh negative
pregnant women
Venous Blood Samples
• Obtain prior to administration of IV fluids or
medications, when possible.
• Use to monitor some antibiotic treatments.
• Use extremity without IV line or stop flow
of fluid or medication to avoid
contamination
• Use blood tubes preferred by individual
laboratories.
Venous Blood Samples
Venous Blood Samples