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Flashcards in Into Lab Med Deck (37)
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qualitative testing definition

either positive/ negative


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

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


Indication for use of each chemistry: ALT
-what does it stand for?

Alanine Amino Transferase

Indication for use:
-enzyme found in liver
-checks for liver damage and liver disease (hept & cirrhosis)
- low levels normally found in blood, w/ damage ALT is increased in blood.


Indication for use of each chemistry:ALP
-what does it stand for?

Alkaline Phosphatase

-checks for liver disease
-bone problems such as rickets,, bone tumors, etc


Indication for use of each chemistry: CO2
-what does it stand for?

Carbon Dioxide

Indication for use:
-acts as buffer, keeps pH of blood from becoming too acidic or basic
-tests for kidney disease, lung disease, and metabolic problems that affect bicarbonate levels


Indication for use of each chemistry:T. Bili & D. Bili
-what doe it stand for?

Total Bilirubin & Direct Bilirubin

Indication of use-
-check for liver function & disease (hept & cirrhosis)
-find if bile duct blocked (gall stones, tumor of pancreas)
- detect conditions that cause increased RBC destruction (such as hemolytic anemia, or hemolytic disease of the newborn)

-direct bili is soluble and made by liver from indirect bili.


Indication for use of each chemistry: Glucose
-what does it stand for?


Indication for use:
-measures glucose levels in the blood
- check for pre/diabetes
-monitor treatment of diabetes
-check for gestational diabetes
-detect hypoglycemia


Indication for use of each chemistry: BUN
-what does it stand for?

Blood Urea Nitrogen

indication for use:
-measures nitrogen in blood from waste product urea
-tests kidney function (if tx is working, if disease is getting better or worse)
* Kidney disease: increase BUN
*Liver diease: decrease BUN
- checks levels of severe dehydration (BUN to creatinin ratio)