Thanks once again to high school co-op student Tyler Beattie for putting this simple but useful app together for Android-based smartphones. The Clinical Diagnosis Helper app asks you to enter know information about the pre-test probability of a condition, the positive (Sn/1-Sp) or negative (1-Sn/Sp) likelihood ratios of the test you're using, and then indicate whether the result of the test was positive or negative. Note that you'll need to corresponding PLR or NLR dependent on whether the test was positive or negative, but don't need both. Hit the calculate button to get the post-test odds that the condition exists. If you thought a nomogram was simple, this is even easier. There are other app options out there that do this, but this one's free and couldn't be easier to use. Hit the link above on your smartphone to download it.