Into Lab Med Flashcards
(37 cards)
qualitative testing definition
either positive/ negative
present/absent
yes/no
quantitative testing definition
measured amount reported in mass or volume; how much
Sensitivity Definition
presence of disease
compare true positives and false negatives
Highly sensitive test that is NEGATIVE is highly good at ruling out disease (SNout)
True positive
————————————-
True positive + False Negative
68% sensitivity = if you take 100 ppl w/ disease you are looking for, how many pt with the disease are going to test positive? 68, so that means 32 people that actually have the disease will get a negative result
Specificity Definition
absence of disease; compares true negatives and false positives
Highly Specific test that is Positive is good for ruling IN the disease (SPin)
True Negative --------------------------------------- True negative + false positive
77% specificity = if you take 100 ppl who do not have the disease, how many pt w/ disease are going to test negative? 77 are going to test negative for the disease, 23 people will get a positive result even though they are negative
List the different kinds of chemistry panels and the tests within them
BMP- Na+, K+, Cl-, CO2, glucose, BUN, Creat, Ca2+
CMP- all of BMP + TP, ALB, AST, ALT, ALP, T. Billi
Liver Function- ALB, AST, ALT, ALP, T. Billi. D, Billi
Renal Function- BMP + ALB, Inor P.
Cell types measured in CBC
WBC, RBC, Platelets
Which type of lab test would you want to order to know types of WBC present?
CBC + WBC Differential
What type of RBC counts are included in a CBC
- RBC count: actualy # of RBC
- Hgb: amount of 02 carrying protein in blood
- Hematocrit: % of RBC
- Reticulocytes: not really part of CBC, but they may be useful in determining acute vs chronic bleed
- A lot of reticulocytes=chronic bleed
- Few= acute bleed
-RBC indices: MCH, MCV, MCHC, RDW
Why do you take careful consideration when ordering specific lab test?
- need to have diagnosis for every lab test
- only order when necessary- be cost effective
- only order test if it changes the treatment plan of patient
- if patient cannot endure test- do not order. ex: Stress test
Precision Definition
is a measure of the tests reproducibility
Coefficient of Variation Definition
precise tests vary slightly upon repetition.
Accuracy Definition
determined by its correspondence with the true value
*maximized by calibration of lab equipment with standard reference material
Normal result: lab test definition
within the reference range
Abnormal result: lab test definition
outside of the reference range
Average result:
lab test definition
mean of reference range
Concepts of risk-benefit- and cost effectiveness in the choice of diagnostic procedures
cost effectiveness- ordering single test may be less expensive than the whole panel or vice versa. dont order test unless it will change your management
- risk/benefit: risks/benefits of types of tests. ex: cerebral angio, stress test
- ALWAYS ask yourself, will the results of testing change management
Reference Intervals are ___ & ____ dependent
lab and population (“healthy”)
Pretest Probability
the likelihood the patient has the abnormality that you are testing for based on risk factors, symptoms, history, and physical exam.
*Range 0-1
0= disease absent
1= disease present
higher the pretest prob. the more likely you will get a true result
Diagnosis-related-Groups (DRG) assignment of appropriate lab testing
are grouped by diagnosis and other factors to determine how much medicare pays for each “product”
CPT and ICD code for….
CPT= procedures ICD= diagnosis
Advantages/ Distadvantages of order a single vs profile lab test
advantage of single- get exactly what you want, may save money
advantage of profile- may be more cost effective than single, extra info that may lead to other findings.
ex. cholesterol testing @ fair, found to have high cholesterol so you end up needing to order another test (lipid panel) prior to treating the patient.
disadvantages of profile &/or single - may be more expensive,
Identify various units of measurements
G (grams) mg/L (milligram/liter) ml (milliliters) mmHg (millimeters of mercury) mmmol (millimole) ng/ml (nanogram/milliliter) U/ml (units/ milliliter) Pg (picograms) Ng (nanograms) mcg (microgram) mcL (microliter) mcmol/L (micromoles/liter) fL (femtoliter)
Indication for use of each chemistry: ALB
Albumin:
Indication for use:
checks kidney and liver function
-helps determine cause of swelling of ankles, abdomen, or fluid collection in the lungs
Indication for use of each chemistry: AST
-what does it stand for
Aspartate Amino Transferase
Indication of use:
-check for liver damage and liver disease (hept. & cirrhosis)
-AST is an enzyme (normally found in blood) that increases during organ disease or damage
