Biochemistry

Question 1

Accuracy in biochem tests =

Answer 1

how close is it to the true value?

Question 2

Precision in biochem tests =

Answer 2

how predictable is the test result?

Question 3

Sensitivity in biochem tests =

Answer 3

chance that you get a +ve test given that you have the disease
+ve and have/all that have
If increased = less false negatives

Question 4

Specificity in biochem tests =

Answer 4

chance that you get a -ve test given that you dont have disease
-ve + dont have/ all that don’t have
If increased = less false positives

Question 5

PPV in biochem tests =

Answer 5

+ve predictive value
have disease given you test +ve
disease and +ve/all +ves
PRB of having disease if told you have it

Question 6

NPV in biochem tests =

Answer 6

-ve predictive value
dont have disease given -ve test
dont have + -ve/ all -ves
PRB of not having if told don’t have

Question 7

Prevalence affects

Answer 7

PPV( directly proportionally) and NPV (indirectly proportionally)

Question 8

If set diagnostic cut off low sensitivity and specificity are ___

Answer 8

sensitivity is high

specificity is low

Question 9

If set diagnostic cut of high specificity and sensitivity are ___

Answer 9

sensitivity is low

specificity is high

Question 10

Buffers of H+ in the blood

Answer 10

bicarbonate (HCO3-) mainly

Hb, phosphate (HPO4 2-), ammonium (NH3)

Question 11

Metabolic causes of acidosis

Answer 11

impaired H+ excretion, increased H+ production/ingestion

antifreezze, loss of HCO3-

Question 12

Causes of metabolic alkalosis

Answer 12

vomiting, alkali ingestion, K+ deficiency

Question 13

ABGs are

Answer 13

H+, pCO2, HCO3-, pO2