PHCH 667 Exam 1 Questions with 100% Correct
Answers | Verified | Sure Pass
What is specificity and how is it measured? - ✔✔true negative rate of test (correctly
identifies those who do not have a disease)
TN/(FP + TN)
What is sensitivity and how is it measured? - ✔✔detects a true positive (correctly
identifies those who have a disease)
TP/(TP + FN)
What is a positive predictive value (PPV) and how is it used? - ✔✔fraction of positive
tests that were correct
TP/(TP + FP)
What is a negative predictive value (NPV) and how is it used? - ✔✔fraction of all
negative results which are true
TN/(TN + FN)
What is the impact of disease prevalence on PPV and NPV? - ✔✔as disease
prevalence decreases:
PPV: DECREASES
, NPV: INCREASE
What are some examples of mishandling clinical samples and laboratory errors that
effect test results? - ✔✔-improper storage/handling
-improper timing of sample collection
-faulty reagents
-controls not working correctly
-technical problems with instruments
-improper calibration
-calculation errors
What are homogeneous samples? - ✔✔mixture where no separation step is required
What are heterogenous samples? - ✔✔mixture where a separation step is required
What are the principles of UV/Vis spec? - ✔✔the concentration of an analyte solution
can be determined by measuring absorbance at a defined wavelength
What are the principles of nephelometry measurement? - ✔✔measures turbidity of a
sample
What does a pH meter measure? - ✔✔measures the pH which is the hydrogen-ion
concentration by taking the difference between two electrodes
What are some examples of techniques used to separate samples prior to analysis? -
✔✔-centrifugation
-filtration
Answers | Verified | Sure Pass
What is specificity and how is it measured? - ✔✔true negative rate of test (correctly
identifies those who do not have a disease)
TN/(FP + TN)
What is sensitivity and how is it measured? - ✔✔detects a true positive (correctly
identifies those who have a disease)
TP/(TP + FN)
What is a positive predictive value (PPV) and how is it used? - ✔✔fraction of positive
tests that were correct
TP/(TP + FP)
What is a negative predictive value (NPV) and how is it used? - ✔✔fraction of all
negative results which are true
TN/(TN + FN)
What is the impact of disease prevalence on PPV and NPV? - ✔✔as disease
prevalence decreases:
PPV: DECREASES
, NPV: INCREASE
What are some examples of mishandling clinical samples and laboratory errors that
effect test results? - ✔✔-improper storage/handling
-improper timing of sample collection
-faulty reagents
-controls not working correctly
-technical problems with instruments
-improper calibration
-calculation errors
What are homogeneous samples? - ✔✔mixture where no separation step is required
What are heterogenous samples? - ✔✔mixture where a separation step is required
What are the principles of UV/Vis spec? - ✔✔the concentration of an analyte solution
can be determined by measuring absorbance at a defined wavelength
What are the principles of nephelometry measurement? - ✔✔measures turbidity of a
sample
What does a pH meter measure? - ✔✔measures the pH which is the hydrogen-ion
concentration by taking the difference between two electrodes
What are some examples of techniques used to separate samples prior to analysis? -
✔✔-centrifugation
-filtration
