13 Flashcards
How do we investigate a patient
patient history
physical exam
imaging
laboratory tests
Why are lab tests ordered
diagnosis
monitor progression of disease
monitor effectiveness of treatment
screening population for diseases
to identify complications of treatment
for predicting survivability, employability
to check the accuracy of an unexpected data
to conduct research
to prevent malpractice
for education
to assess nutritional status and health of a ahealthy individual
responding to total uncertainty
What are the types of patient samples that are excreted
urine
stool
selaiva
semen
sweat
hari
What are types of patient sample s that are within the body
blood
CSF
amniotic fluid
tissue (biopsy)
bone marrow
What biochemical molecules could provide insights into a person’s heatlh
electrolytes
- potassium
- sodium
LDL cholesterol
lipids, lipoproteins
vitamins
uric acid/urea
Describe lab organization
core lab facility
- hospitals
- operates 24/7
- most essential and requested tests
- highly uatomated
- multi-analyte capabilities
special chemistry
- less frequently ordered tests
- labour intensive and often manual methods
- non-stat tests (not required imediately)
point of care testesting
- outisde of chemistry laboratory (CCU, ER, ICU, clinic)
Describe the core lab
high volumte tests (many per day)
often requriing a quick turn around time
provide critical information on client health
- electrolytes: sodium, potassium, chloride
- blood gases: pO2, pCO@, pH, HCO3, oxygen sat
- endocrine: thyroid hormones, prolactin, testosterone, estrogen, FSH, LH
- lipids: total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides
- proteins: total protein, liver proteins (albumin, immunoglobulins
- glucose:
- tumor markers
- bitamins, minerals (trace elemetns)
- toxicology
What are the elements of the point of care testing
- urgent importance
- affect immediate management of the patient (can be used at home)
- available that can perform at remote locations
(blood glucose, urinalysis, blood gases, electrolytes, cardiac markers, drug screens, COVID) - many are immunoassay based
- qualitative or quantitative
how do tests work
measure an analyte as a marker to distinguish health and disease
What are ideal markers
absolutely specific for a specific disease
easily measurable
quantity reflective of severity of disease
early detection following onset of disease
not affected by other biological disturbances
What is troponin T
what is an example
highly specific marker
- marker of myocardial infarction
- found predominately in cardiac tissue
- released into hte blood following cardiac cell death
What is an example of a non-specific marker
low blood pH
- very important to know but can be caused by many pathologies
(medications or drugs, resp problems, renal problems)
What is the source of bllodo
veins
arteries
skin puncture - capillary blood
What is the collection method of blood
syringe
evacuated tube (additives, seperator gel)
intravenous lines
What are factors affecting choice of blood source and collection method
analyte under investigation
patient (vascular status, ease of collection)
What is blood, plasma and serum
whole blood is red fluid that is removed from a vein into a tube
plasma is the protein containing fluid portion of the blood, after centriugation to remove red and white blood cells and platelets
serum is the clear fluid left after blood is alllwoed to clot and then centrifuged – plasma without the blood clotting proteins
What happens when blood is centrifuged
- plasma (PRP)
- plasma is fluid component of blood
- comprises ~55% of total volume of blood
- contains proteins, sugars, vitamins, minerals, lipids, lipoproteins and clotting factors
- 95% of plasma is water - buffy coat
- WBC and platlets - hemtocrit
- RBC
When is insoluble firbin clot formed
if blood is allowed to stand without anti-coagulants
how does serum form
if blood is centrifuged, it is the fluid portioin
What are the parts of serum
serum
- ~55% of total volume of whole blood
- proteins, sugars, vitamins, minerals, lipids, lipoproteins
- no clotting factors
- 95% serum is water
clotted blood
- RBC, WBC
- clotting factors (fibrin, platelets)
What are collection tubes
most widely used tubes for blood collection evacuated
- negative prersure facilitates collection
- easy to use
- sterile
- universally colour-coded rubber stoppers denote tube type
What are tubes additives
various anticoagulatns for the collection of whole blood or plasma
- additives for specific tests
What do red-top tubes indicate
contain no anticoagulants or preservatives
used for collecting serum
- 10-15 minutes is requred to allow blood to clot before centrifuging
- used for blood bank specimens and chemistry
What do gold-top tubes indicate
contain a gel that forms a physical barrier between the serum and cells after centrifugation
- no other additives present
- gel barriers may affect some lab tests