 Here's where ProPublica's helper is tops. Just answer a few questions and it creates a PDF request letter. Your insurer must respond within 30 days. ProPublica can also follow up to make sure they get your file. Some patients have found denials were due to cost cutting or just plain mistakes. Know your rights. Visit projects.propublica.org. That's projects.propublica.org. And by the way, if you need that address again, just use the search tool on my website.