wk3- pathology testing Flashcards
is there medicare rebate for pods when referring pt to pathology
no- so best to go through with GP
types of pathology testing
1.kidney function (creatinine, eGFR)
2. hepatic function (LFTs - liver function tesst)
3. microbiology (bacterial, fungal)
4. aspirates
5. blood tests (ESR, CRP, FBC/CBC)
6. histology
reasons for pathology testing
- identifying dysfunction
- guides pharmacotherapeutics
- monitors response to treatment
ways the liver helps with metabolism
- functionalisation (addition of a functional group to make it more water soluble)- CYP450 enzymes help with this
- conjugation reaction (addition of polar group from endogenous substance to the drug
liver function tests tell us what
-screen liver damage
-tracking acute liver disease on a day by day basis
-response to treatment
-tests do not always correlate with severity or prognosis
-can still have normal LFTs and have liver function issues
Example:cirrhosis can have normal LFTs
-abnormal LFT is common and may reflect problems outside the liver
patterns of liver function tests
- hepatocellular- injury to hepatocytes
2.cholestatic- injury to bile ducts
what are you testing with an LFT
Concentrations of
- alanine aminotransferase (ALT)- linked to hepatocellular damage
- aspartate aminotransferase (AST)- hepatocellular damage, same as ALT
- Gamma glutaryl transferase (GGT)-
which can be caused by:
-viral infections
-drug/alcohol abuse
-viral infection
-anoxia
-obstruction
ratio of ALT/AST can indicate what
severity of condition
normal- 1.15
deviations above and below this indicates disease, and the further away, the more severe
examples in lecture slides
elevated levels of gamma glutaryl transferase (GGT) may indicate what?
Cholestasis
* Enzyme induction
* Alcohol, phenytoin, barbiturates, rifampicin
* Congestive heart failure
* Cirrhosis
* Hepatic ischemia, necrosis, or tumour
* Hepatitis
* Hepatotoxic drugs.
if there is hepatic impairment or low therapeautic index what is the best thing to do when initiating drugs that are cleared by the liver
reduce dose by 50%
major functions of the kidney
- Filtration of blood:
* Removes metabolic wastes from the body, esp. those containing nitrogen - Regulation/ reabsorption
* Blood volume and composition
* Electrolytes
* Acid-Base Balance
reabsorb essential compoounds - Endocrine:
* Erythropoietin (EPO)
* Renin
* 1,25 dihydroxycholecalciferol (1,25 Vitamin D) - Secretion through urine
Glomerurlar filtration rate
volume of plasma filtered
approx- 180L/day (1-2L/day loss through urine and 99% of filtrate is reabsorbed)
approx urine output
1-2L/DAY
How much filtrate is reabsorbed
99%
180L- GFR
1-2L - urine
what influences GFR
-BP and flow
-obstruction to urine outflow
-loss of protein free fluid
what makes up renal clearance
Glomerular filtration
secretition
passive rebsorption
what changes are made to drugs when renal function is less than 50% and the drug is cleared by kidneys more than 50%
dose adjustments
main site for clearance of water soluble drugs from the blood
kidneys
why is kidney function important for drug use
if there is renal impairment, normal amounts of drug consumption will eventually exceed the amount of drug being cleared and plasma levels will continue to rise causing toxicity
example of antibiotics cleared by the kidneys (renal)
penicillins and cephalosporins
renal function tests include
- creatinine clearance
-waste product of skeletal muscle breakdown that can only be excreted by filtration (no reabsorption), this is used to measure the GRF of kidneys
-cockcroft gault formula - eGFR
-uses serum cretinine, age, gender, ethnicity to calculate
normal eGFR values for 20-70 YRS OLD
20- 116mL
40- 99mL
60- 85mL
70-75mL
the older you get the lower the renal clearance
downfalls of creatinine clearance testing
very expensive and time consuming
as people age, their GRF levels change therefore
they will need dose adjustments as their clearance will decrease
ways you can adjust dose for renal/heptic impiarment
- reduce dose amount
- extend dosing interval
- both
drugs that may require dose adjustments in RENAL impairment (kidneys)
- antibiotics - Amoxicillin, Amoxicillin plus Clavulanic acid, Cefalexin, Ciprofloxacin, Dicloxacillin, Flucloxacillin, Roxithromycin
- antifungals - terbinafine
- opiates - codeine
- gout - colchicine
AMH have dose adjustment recommendations
when is microbiology typically used by a pod
in a hospital setting
what types of microbiology are there
- swab
- biopsy/aspirate
- blood culture
different types of culture based tests
- disk diffusion
- broth dilution
- agar dilution
used to diagnose and direct treatment with anti microbials for bacterial infections
fungal microscopy v culture time period
microscopy quick
culture slow (approx 4 weeks)
when would u use a aspirate
needle that draws out fluid
- septic arthritis
-septicemia
- gouty arthritis
what is CRP
globulin released by the liver during an inflammatory reaction
what can elevated CRP indicate
- acute infection
-diabetes/obesity
normal - 5mg/L
what is CRP not good for
chronic inflammation,
it is an acute phase marker
ESR what is it
aggregation of RBCs increases ESR
what is ESR good at indicating
-chronic phase inflammation
what is CBC (complete blood count) good for
diagnosising
-anaemia
-thromboctyopenia
-viral fevers
-autoimmune conditions
-infections
-nutrition defiencies
-haemopoitic malignancies
monitor drug therapy
neutrophils react to what
bacterial infection
lymphocytes react to what
viral infection
monocytes react to what
chronic inflammation
eosinophils react to what
parasitic infection
basophils react to what
allergic response
histopathology
examining of tissue for disease
-cancer
-growths
if a patient has a bacterial infection in foot what blood tests could help with diagnosis and treatment
complete blood count- change in WBC showing infection
CRP- for acute infection phase
is 8.4% HBA1C concerning in an 88yr old, what other test could we look at
measure of glucose bound to RBC
if they’re older than its less of a concern because as people age, they have a higher chance of anaemia - this causes glucose binding to the small amount of RBC which pushes up his HBA1C
so you would want to look at his RBC tests to see if he is anaemic and this can explain the high HBA1C
how often are you meant to measure BGL
multiple points during the day according to guidelines
not just one in the morning
liver function tests reveal what?
its not a direct measure of liver function
it represents liver damage (when it is damage it releases these eznymes ALP, ALT, GGP,etc)
However, they can also be elevated in damage to different areas not the liver (eg damage to bone can cause an increase in these enzymes)
why shouldnt you swab all wounds
limited sensitivity and specificty to wound swabbing
every wound is colonised with bacteria and if you swab youll probably grow something and not need to treat it
antimicrobial stewardship, there needs to be clinical signs of infection
what do you place a wound swab into (formalin or saline)
formalin- good for preserving tissues- kills bacteria (not good for wound swabs)
saline- want to keep bacteria alive so saline is used
if someone is on dialysis what does that mean
kidney function is severely declined to the point where they would die if they weren’t from toxicity
what would you do with someone on dialysis
dose adjustments- need multiple people to work on this
what tests could you use for a swollen, red hot joint
joint aspiration- referral
xray
systemic symptoms (fever, respiratory, HR)
what do prescriptions need to include
full details of prescriber
name, qualifications, profesion (pod with ESM), PBA registration number, practice address
patients name, address, DOB
medication, quantity, form, dose, number of repeats
directions for use (unless complex, itll be on another form)
signed by prescriber
how long is an S4 prescription valid for
12 month
how long are s8 prescriptions valid for
6 months
low RBC means
anaemic
low neutophils and lymphocytes means
leuokopenia- makes the patient at risk for infections because dont have adequate WBC to fight infections
D-dimer test and thrombosis
????
INR means
clotting time
