A BNP (B-type natriuretic peptide) blood test measures a hormone your heart releases when it's strained or failing to pump efficiently. Doctors order it to diagnose heart failure, assess its severity, or monitor treatment effectiveness. Normal BNP levels typically fall below 100 pg/mL, while levels above 400 pg/mL suggest heart failure. Levels between 100-400 pg/mL require clinical judgment based on symptoms and other factors. This question has nothing to do with link building, SEO, or web strategy—it's a medical topic that likely reached us through a misdirected search or form submission. If you're researching health content for a medical website or blog, the SEO angle would be understanding search intent: users typing "what is bnp blood test" want clinical information, reference ranges, and what abnormal results mean. They're not looking for link building advice. For agencies running content portfolios, this kind of query-category mismatch happens when intake forms lack proper validation or when AI tools misclassify questions. At Ottawa SEO Inc., we segment questions by pillar during intake specifically to avoid this—link building questions should cover tactics like digital PR, broken link building, resource page outreach, or competitor backlink analysis. If you genuinely need SEO guidance for medical content: health queries like BNP tests fall under YMYL (Your Money Your Life) categories where Google demands expertise, authoritativeness, and trustworthiness. You'd need physician reviews, proper citations to medical sources like peer-reviewed journals, and author bios demonstrating medical credentials. Link building for health content focuses on earning links from hospital networks, medical associations, and .edu domains—not guest posts on generic health blogs. But again, that's content strategy, not what this pillar covers.