Lab Medicine

Question 1

Accuracy

Answer 1

how closely the test results correspond to the true value or “gold standard.”

Question 2

Precision

Answer 2

How reproduce-able the results are with repeat testing of the same specimen

Question 3

Specificity

Answer 3

measures TN–> the percentage of persons WITHOUT the disease of interest with negative test results–>higher specificity of the test, the more likely it is that persons without the disease of interest will be excluded from consideration of having the disease

Question 4

What kind of test is used to clinically rule IN the disease?

Answer 4

Specificity (SPIN)

Question 5

T/F: The lower the specificity, the higher the chance of a false positive result

Answer 5

TRUE

Question 6

Sensitivity

Answer 6

measures TP –> higher the sensitivity, the more likely to detect people WITH the dz

Question 7

What is used to clinically to rule OUT the presence of the disease in an individual

Answer 7

Sensitivity (SNOUT)

Question 8

Predictive value

Answer 8

Measures concerning to estimation of the probability of the presence or absence of disease.

Question 9

Positive PV

Answer 9

percent of persons with a positive test result who DO HAVE the disease in question

Question 10

Negative PV

Answer 10

percentage of persons with a negative test result who DO NOT HAVE the disease in question

Question 11

False positive

Answer 11

lab testing that identifies abnormalities that are NOT present.

Question 12

False negative

Answer 12

lab testing that fails to identify abnormalities that ARE present.

Question 13

Prevalence

Answer 13

the proportion of a population found to have a condition (typically a disease or risk factor) at a particular time.

Question 14

Likelihood Ratio

Answer 14

Probability of a result in a patient with or without disease

Question 15

Negative LR

Answer 15

Probability of negative test in non-diseased person/ Probability of negative test in a diseased person

Question 16

Pretest probability

Answer 16

the probability of the target disorder before a diagnostic test result is `known

Question 17

Posttest probability

Answer 17

the probability of the presence of a condition (disease) after a diagnostic test.

Question 18

Gold Standard

Answer 18

most accurate measure

Question 19

Narrative result

Answer 19

descriptive values (ie: path report/ Chest Xray report)

Question 20

five major reasons for ordering a laboratory measurement

Answer 20

1) Discover occult (not accompanied by readily discernible signs or symptoms) disease or recurrent disease
2) Confirm a suspected diagnosis
3) Differentiate among possible diagnoses
4) Determine the stage, activity, or severity of disease
5) Assess and monitor the effectiveness of therapy or treatment

Question 21

Qualitative result

Answer 21

Yes/No or Positive/Negative (ie: pregnancy test, rapid strep)

Question 22

Quantitative

Answer 22

Numerical

Question 23

Reference Interval

Answer 23

range of “normal” values

Question 24

T/F: 1 in 20 “normal” tests will have test results outside of the reference range.

Answer 24

TRUE

Question 25

Basic Metabolic Profile (BMP):

Answer 25

common serum electrolytes (Na+, K+, Cl-), carbon dioxide content, blood urea nitrogen, Ca++, creatinine, and glucose

Question 26

Complete Metabolic Profile (CMP):

Answer 26

all BMP components plus albumin, alanine aminotransferease (ALT), aspartate aminotransferease (AST), total bilirubin, and total protein

Question 27

erythrocyte sedimentation test

Answer 27

non-specific test; increases in ESR (erythrocyte sedimentation rate) = infection, inflammation, and plasma cell dyscrasias

Question 28

spun hematocrit

Answer 28

percentage volume of blood that is composed of erythrocytes (RBCs)

Question 29

STAT laboratory tests

Answer 29

needed immediately; given highest priority

Question 30

pinworm prep

Answer 30

Test for the presence of pinworm eggs on the anus

Firmly press the sticky side of a strip of tape over the anal area for a few seconds. The eggs stick to the tape. The tape is then transferred to a glass slide, sticky side down, where it can be examined

Question 31

dipstick urinalysis

Answer 31

tests urine for protein; pH; specific gravity; bilirubin, bile, and urobilinogen; blood and hemoglobin; leukocyte esterase; nitrite; glucose; and ketones

Question 32

fecal occult blood testing (FOBT):

Answer 32

simple screening test, detects presence of blood in stool

Question 33

common sources of error that can affect the quality and variation of laboratory tests

Answer 33

patient variables (ie: BMI, age, gender, meds, pregnant, smoker, etc)

speciment collection variables (ie: posture, time of collection, fastings, presence of IV, etc)

specimen handling variables (ie: sunlight, temp, evaporation, hemolysis, lipemia, etc).

Question 34

urine pregnancy test

Answer 34

detects the presence of a hormone called human chorionic gonadotropin (hCG) in urine

Question 35

wet mount

Answer 35

vaginal discharge is placed on a slide in a salt solution to help detect the cause of vaginitis or vulvitis. The slide is looked at under a microscope for bacteria, yeast cells, trichomoniasis (trichomonads), white blood cells that show an infection, or clue cells that show bacterial vaginosis.

Question 36

potassium hydroxide (KOH) mount

Answer 36

tests for yeast infection – A sample of the vaginal discharge is placed on a slide and mixed with a solution of potassium hydroxide (KOH). The KOH kills bacteria and cells from the vagina, leaving only yeast for easier detection of a yeast infection

Question 37

capillary blood glucose (CBG):

Answer 37

measures blood glucose level, performed by piercing the skin (typically, on the finger) to draw blood, then applying the blood to a chemically active disposable test-strip.

Question 38

ovulation test

Answer 38

helps determine expected ovulation by picking up the luteinizing hormone (LH), LH is always present in urine and increases 24-48 hours prior to ovulation

Question 39

what is the strongest predictor of risk?

Answer 39

age