General Lab Testing Guides
Everyday lab testing topics: how tests work, how to read results, and what to order.
What these guides cover
General lab testing guides cover the questions people ask most often: what a basic panel includes, how to prepare, how results are reported, and how to choose between a single test and a panel. Start here if you are new to ordering your own lab work and want a clear overview before you pick a specific test.
Ordering your own lab work usually starts with a clear question, such as checking a vitamin level, reviewing cholesterol, or following up on a symptom your clinician has already noted. A single test can answer a narrow question, while a panel groups related markers and can cost less than ordering each test on its own. Preparation varies: some tests need fasting, some need to be drawn at a specific time of day, and others need no preparation at all. The guides below note these details in plain language so you can arrive at the collection site ready.
How to use these guides
Each guide below focuses on a single test or a small group of related tests. Start with the marker you and your clinician have discussed, then follow the related-test links to see what is often ordered alongside it. Preparation and timing instructions appear in each guide, and where testing is available is listed by state and city. These guides are educational and do not replace advice from a healthcare provider.
CBC Blood Test Explained: What Your Results Can Mean
Learn what a complete blood count measures, what red and white cell and platelet results can mean, and how to order a CBC at a lab near you.
Iron and Ferritin Testing Guide: What Results Mean
Learn how iron and ferritin testing works, how these markers differ, what low or high results can mean, and how to order testing at a lab ne
Urinalysis Test Explained: What Your Results Can Show
Learn what a urinalysis test measures, what protein, blood, and other findings can indicate, and how to order urinalysis testing at a lab ne
Vitamin B12 Deficiency Testing: Symptoms and Tests
Learn how vitamin B12 deficiency testing works, which markers are used, what low results can mean, and how to order B12 testing at a lab nea
Vitamin D Testing Guide: Who Needs It and What Results Mean
Learn how vitamin D testing works, what 25-hydroxy results mean, who may need testing, and how to order a vitamin D test at a CLIA-certified
Wellness Blood Panel Guide: Tests and What to Expect
Learn what a wellness blood panel includes, which markers are commonly bundled, and how to order a wellness panel at a CLIA-certified lab ne
General Lab Testing FAQ
What is the difference between a single test and a panel?
A single test measures one marker, while a panel groups several related markers into one order. Panels are often used for a broad first look and can be more economical than ordering each test on its own.
How do I prepare for a general lab test?
Preparation depends on the test. Some require fasting for 8 to 12 hours, others need a specific draw time, and many need no preparation. Check the preparation notes for each test before you book.
How are results usually reported?
Results are reported as a value next to a reference range, which is the interval most labs consider typical for a healthy population. A value outside the range is a prompt for a conversation with a clinician, not a conclusion on its own.
Reviewed by the LabDirectories Editorial Team
Our team researches and fact-checks all content to ensure accuracy. We update guides regularly to reflect current testing options, pricing, and laboratory accreditation standards.