Zusammenfassung der Ressource
Laboratory Medicine
- Laboratory tests
- Routine Tests
- on blood and urine
- Blood with or without anticoagulants
- Serum
- no anticoagulant
- general usage
- defibrinated plasma
- cannot be used to study coagulation factors
- Plasma
- EDTA
- Coagulation factors, RBCs,
Lipids and lipoproteins
- Lithium Heparin
- General usage
- fluoride oxalate
- glucose, lactate
- Specialized Tests
- sent to specialized
reference laboratories
- Examples
- VIP
- PTHrP
- DNA analysis
- Troponin
- Emergency Tests
- samples obtained during
surgery or as ER work up
- intraoperative testing of PTH
- determine if PTH-secreting
adenoma was removed
- Qualifications of a "Good" Test
- Precision
- same result on same
sample every time
- Accuracy
- how close measured
value is to true value
- Specificity
- measures incidence of "true negative"
- Spec = (TN/(TN+FP)) * 100
- Sensitivity
- incidence of true positives
- Sen = (TP/(TP+FN)) * 100
- Predictive Value
- Positive Test
- = (TP/(TP + FP)) * 100
- Negative Test
- = (TN/(TN + FN)) * 100
- Water and Sodium
- Water in comparments
- Intracellular volume
- potassium most important here
- Extracellular volume
- interstitial compartment
- Plasma
- sodium most important here
- 70 kg man has 4200 mmol Na+
- [Na+] ~ 135-145 mmol/L
- Depends on Kidneys and hormone
- Thirst
- ADH
- Aldosterone
- Atrial Natriuretic Peptide
- Sodium is a part of...
- Acid-Base balance
- Cell membrane polarity
- Osmolality of body fluids
- Sodium is primary determinant
- Os = (2*Na)+(glu/18)+(BUN/2.8)
- Hyponatremia
- Dilutional
- increased water intake
- infusion of water
- decreased excretion of water
- Hypoproteinemia
- Shift of water from cells into ECV
- SIADH
- Depletional
- Gastrointestinal Loss
- Vomiting, Diarrhea, sequestration
of fluid in intestine, fistulas
- Renal Loss
- Diabetes mellitus, hypercalcemia, salt-wasting
kidney disease, diruetics, Addison's disease
- Dermal Loss
- Burns
- [Na+] < 136 mmol/L
- Symptoms
- usually asymptomatic
- depressed
transmission of neural
or neuromusclar signals
- Hypernatremia
- [Na+] > 150 mmol/L
- Water Loss
- Renal loss of water
- Diabetes insipidus (central
or nephrogenic), renal
tubular necrosis, diuretics
- GI loss of Water
- Diarrhea, vomiting, nasogastric
suction tube, osmotic cathartic agents
- Dermal Loss of water
- Sweating, burns
- Excessive Sodium
Intake or Retension
- Adrenal cortical lesions
- hypercortisolism
- Corticosteroids
- Infusion of sodium-rich solutions
- Frequently from
Dehydration
- Chloride
- Major extracellular anion
- linked to intake, excretion
and metabolism of Na+
- [Cl-] ~ 98-106 mmol/L
- Hyperchloremic metabolic acidosis
- depletion of
bicarb,
replaced by
organic
anions
- can be filled by Cl-
- no hypernatremia
- Hypochloremic metabolism alkalosis
- loss of Cl- in GI tract, filled with bicarb
- Potassium
- intracellular cation
- [K+]~ 3.5-5.0 mmol/L
- Maintained by Kidneys
- excrete 100 mmol a day
- secreted and diffusion
- aldosterone promotes
secretion of K+
- Cellular States
- Normal Cell
- Higher K+ in cell
- Damaged Cell
- Hyperkalemia
- Acidosis
- Hyperkalemia
- Alkalosis
- Hypokalemia
- Insulin promotes
cellular uptake of K+
- Maintained by
Na+/K+ ATPase
- Hypokalemia
- increased loss of K+ in urine
- redistribution of K+ into cells
- GI loss
- Symptoms
- Cardiac Arrhythmias
- Neuromuscular
- weakness and hypotonia
- Slow GI peristalsis
- decreased concentrating
capacity of the kidneys
- Hyperkalemia
- reduced excretion
- Massive tissue
injury or cell lysis
- Redistribution from ICV to ECV
- Symptoms
- Cardiac Arrhythmias
- Acid Base Balance
- Buffer system
- H+ is buffered
using bicarb to
maintain
constant pH
- Kidneys can
regenerate
bicarbonate
- Can also
remove H+
- Metabolic Acidosis
- accumulation of
H+, reduced HCO3
- compensate by exhaling
CO2, decreased pCO2
- Loss of bicarb
- DI tract through diarrhea,
intestinal, pancreatic, biliary
drainage
- inability to excrete H+
- Kidney failure, hypoaldosteronism
- Excessive endogenous acids
- diabetes mellitus
- Ingestion of fixed acids
- high anion gap
(sometimes)
- adding acid does
- Metabolic Alkalosis
- loss of H+ or HCO3 retention
- reduced breathing
- ECV contraction
- Potassium
Deficiency
- Mineralocorticoid
Excess
- Respiratory Acidosis
- retention
of CO2
- kidneys
retain
HCO3
- Excess CO2 is buffered as HCO3
- Increased H+ in blood
- hypoxia
- Symptoms
- increased blood flow to
brain, reduced cardiac
output, pulmonary HTN
- Respiratory Alkalosis
- excessive loss of CO2
- increase excretion of HCO3
- From hyperventilation
- Symptoms
- hypocapnia, light
headedness, syncope
- perioral and peripheral
paresthesia
- Calcium
- Extracellular Ion
- Concentration
depends on pH of
blood, [albumin],
- reduce during
respiratory alkalosis
- [Ca +2] ~ 8.4 - 10.2
mg/dL (2.2-2.6
mmol/L)
- Free, protein
bound, anion bound
- Albumin and globulins are
calcium binding proteins
- increased [protein
bound Ca2+]
- Dehydration
- Paraproteinemia
- Hypoalbuminemia
- low total
serum calcium
with no clinical
evidence
- Hypocalcemia
- caused by
hypoalbuminemia
- Alkalosis
- less free H+, albumin
will bind calcium more
- With hyperphosphatemia
- Hypoparathyroidism
- surgery or DiGeorge Syndrome
- Chronic Renal failure
- Inadequate Vit D hydroxylation
- Hypomagnesemia
- normally help form PTH
- with hypophosphatemia
- Inadequate intake of Vit D
- Rickets
- Intestinal Malabsorption
- Renal or Liver Disease
- Drug related
- Neonatal
- Inborn errors of met.
- Symptoms
- Neuromuscular numbness, parestheisa, spasms,
- abnormal heart
rhythm, prolonged QT
- Lack of alertness,
convulsions, loss of
consciousness
- laryngeal stridor
- Hypercalcemia
- Hyperparathyroidism
- Primary
- parathyroid
adenoma or
hyperplasia
- Secondary
- chronic renal disease
- Tertiary
- becomes
independent
of [Ca2+]
- Neoplasia
- malignant tumors
- bone
metastases
- PTHrP
- Multiple
Myeloma
and
Lymphoma
- Vitamin D intoxication
- Granulomatous Diseases
- TB, sarcoidosis, fungal infections
- Hyperthyroidism
- Usually
asymptomatic
- Renal: polyuria, polydipsia, renal calculi, nephrocalcinosis
- Muscle/Skeleton: pain, fractures, weakness,
- Neuro: weakness, fatigue
- GI: abdominal pain,
anorexia, constipation
- Cardio: arrhythmia, ECG, arrest
- Phosphorus
- Mostly in bones
and teeth, some
inside cells (little
in serum)
- phosphates filtered in
kidney are reabsorbed
- Hypophosphatemia
- inadequate absorption or increased loss or shiftfrom compartment
- antiacids may block absorption
- alkalosis
- increased insulin
- Symptoms
- muscle weakness, cardiac arrhythmia, confusion
- reduction of
2,3-diphosphoglycerate
in RBC
- Hyperphosphatemia
- chronic renal failure preventing excretion
- reduces calcium
- Massive Cell Lysis
- Leads to hypocalcemia and
metastatic calcification
- Proteins
- plasma proteins
mostly from the liver
- Immunoglobulins
are the exception
- Albumin and Globulin
- 3:1 ratio normally
- Electrophoresis
- will separate into 5 bands
- fetal and newborn blood have 6
- prealbumin
- Albumin
- oncotic protein in blood
- buffer
- source of amino acids for other proteins
- transport protein for calcium, FFA,
bilirubin, hormones, drugs, etc
- antioxidant
- regulator of capillary permeability
- Others
- alpha1-globulin
- alpha-antitrypsin
- serine protease inhibitor
- alpha fetoprotein
- major fetal protein,
- alpha2-globulin
- alpha2-macroglobulin
- protease inhibitor
- increase in nephrotic syndrome
- haptoglobin
- binds free hemoglobin
- ceruloplasmin
- ferroxidase activity,
transports copper and
iron
- acute
phase
protein
- beta-globulin
- transferrin
- iron-transporting protein
- complement factors C3 and C4
- inflammatory and
immune reaction
- B2-microglobulin
- light chain of class 1 leukocyte antigen
- Fibrinogen
- coagulation when fibrin
- gamma-globulin
- immunoglobins
- C-reactive protein
- present during
infection,
rheumatoid arthritis,
etc.
- Diagnostic Proteins
- Aminotransferases
- Aspartate aminotransferase
- Alanine Aminotransferase
- leak out of damaged livers
- Alkaline phosphatase
- healthy: from bone
- marker of biliary obstruction
- Lactate Dehydrogenase
- high in neoplastic states
- cell damage
- Creatine Kinase
- muscle injury
- CK-MB in
myocardial
infarction
- Blood Urea Nitrogen
- high in renal failure,
shock, volume depletion
- GI bleeding, stress, drugs, corticosteroids
- Low: starvation, liver failure, polyuria,
- Creatinine
- kidney failure
- Lipids and Lipoproteins
- complexed with apoproteins in whater
- chylomicrons, VLDL, LDLs, HDLs
- Hyperlipidemia
- primary (genetic)
- elevation of cholesterol and TGs
- secondary dislipoproteinemias
- from diabetes, obesity, alcoholism,
hypothyroidism, nephrotic syndrome, biliary
obstruction, antihypertensive drugs
- Carbohydrates
- stored as glycogen
- Hyperglycemia
- Diabetes Mellitus
- Hypoglycemia
- overtreatment
of diabetes