What does sensitivity mean? 
{{c1::The probability a test is positive in a patient who has the disease}}

What does&nbsp;<b>sensitivity</b>&nbsp;mean?&nbsp;<br>{{c1::The probability a test is <u>positive</u>&nbsp;in a patient who&nbsp;<u>has</u>&nbsp;the disease}}

Formula:
 \(\text{Sensitivity} = \frac{\text{True Positives}} {\text{No. of people with the disease}}\)

A sensitive test is one that's really good at picking up everyone who has the disease i.e. low false negatives.

If it's not very specific, you will often get a positive result in people despite them not really having the disease i.e. high false positives.

This means that if a test is sensitive but not specific and it comes back negative you can be pretty sure they don't have the disease.
If it comes back positive you can't be sure if its a true positive or a false positive.

Thus a sensitive test is good for ruling out a disease.

Formula:<br>&nbsp;\(\text{Sensitivity} = \frac{\text{True Positives}} {\text{No. of people with the disease}}\)<br><br>A sensitive test is one that's really good at picking up everyone who has the disease i.e. low false negatives.<br><br>If it's not very specific, you will often get a positive result in people despite them not really having the disease i.e. high false positives.<br><br>This means that if a test is&nbsp;<i>sensitive</i>&nbsp;but not&nbsp;<i>specific</i>&nbsp;and it comes back negative you can be pretty sure they don't have the disease.<br>If it comes back positive you can't be sure if its a&nbsp;<i>true positive</i>&nbsp;or a <i>false positive.</i><br><br>Thus a sensitive test is good for&nbsp;<u>ruling out</u>&nbsp;a disease.

<div><div>Shreffler J, Huecker MR. Diagnostic Testing Accuracy: Sensitivity, Specificity, Predictive Values and Likelihood Ratios. [Updated 2023 Mar 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557491/</div></div>