Interpreting Test Results Flashcards
what are the clinical steps for determining type of infection
consultation, history/exam/ report differential diagnosis, choose test to decipher which it is
what are the three types of research within chemical pathology
service discipline - performs test, provide advice, clinical protocols
major clinical science - biochemical basis of disease and science of diagnosis
major interests - physiological exams, endocrinology, metabolism
what are the 4 normal contents within a lab report
demographic details
results
reference ranges
comments and advice
how do we identify abnormal biochemistry
use a “normal range”
artificial concept - no real boundaries exist
therefore used as “reference range”
patients would have +-5% of range
what are the two criteria for an ideal test
high specificity and sensitivity - rarely available cohabiting
what strategies are there to improve tests
select a more appropriate normal population
use a combination of tests to achieve diagnostic goals
give an example of combing tests for better results
neonatal screening for PKU and hypothyroidism
sensitive first line test
then specific test for screen positive (higher cost)
what is an appropriate “normal” population
patients with similar symptoms
same: age, gender, underlying disease
diet, pregnancy, time of day/year
what is the 2 line 2 range test used to distinguish between
between positives and false positives
reference line is adjusting in the sensitive screening - any positive past this point (could be negative) have a specific test which can differentiate between positive and false positive
as an example how are levels of cortisol measured
between 9 and 12 am due to narrow reference ranges
cortisol is diurnally controlled
as an example how is the glucose tolerance test carried out
(outdated now)
75mg given, if there is glucose intolerance produces diabetic curve as glucose remains high
how do action limits aid interpretation of results
when reference ranges aren’t useful eg cholesterol and paracetamol - no normal range should be in the body
what are therapeutic ranges used for
for drugs to show thresholds of effective (low) and toxic (high) eg lithium and digoxin
what equation is used to help monitor long term diabetes
protein + glucose = advanced glycosylated end products (AGE)
non-enzymatic, rate of formation is proportional to glucose concentration and time (good monitoring test)
what is another identifying molecule which provides evidence of developing diabetes related complications
HbA1c - joins with glucose in the blood
its percentage concentration indicates cumulative glucose exposure
higher the level the higher the risk of developing complications
