Immune Workup: What It Is, When It's Needed, and What Tests Are Involved

When your body keeps getting sick—cold after cold, sinus infections, or pneumonia that won’t quit—it’s not just bad luck. It might be your immune workup, a series of lab tests designed to evaluate how well your immune system is functioning. Also known as immune function testing, it’s the go-to tool doctors use when infections don’t behave normally. This isn’t about checking for one specific disease. It’s about asking: Is your immune system missing pieces? Overreacting? Or just tired out?

An immune workup, a series of lab tests designed to evaluate how well your immune system is functioning. Also known as immune function testing, it’s the go-to tool doctors use when infections don’t behave normally. typically starts with a complete blood count (CBC) to see if your white blood cell numbers are low, high, or weirdly mixed. Then come the antibody tests—like IgG, IgA, IgM—that measure your body’s ability to make defenses against viruses and bacteria. If those are off, doctors may check for immunodeficiency, a condition where the immune system doesn’t work well enough to fight off infections, which can be inherited or caused by long-term meds like steroids. On the flip side, if your immune system is attacking your own tissues—like in lupus or rheumatoid arthritis—it’s looking for autoimmune disorders, conditions where the immune system mistakenly targets healthy cells. These aren’t rare. They show up in people who’ve had unexplained fatigue, joint pain, or rashes that don’t go away.

Some people get repeated ear infections, others struggle with chronic diarrhea from gut bugs. That’s where antibody levels, the measurable amount of protective proteins your immune system produces in response to infections or vaccines matter. Low IgG? You might not respond well to vaccines. High IgE? Could point to allergies or parasitic issues. These aren’t just numbers—they explain why one person gets sick every winter and another stays healthy.

You won’t find an immune workup in a routine checkup. It’s ordered when things don’t add up: frequent infections, poor response to treatment, or unexplained symptoms that point to immune trouble. It’s not about boosting your immunity with supplements. It’s about finding the real problem so you can fix it—whether that means switching meds, starting IVIG, or adjusting your lifestyle. The posts below cover exactly this: how steroids mess with your immune response, how probiotics help when antibiotics knock out your good bacteria, how cumulative drug toxicity slowly weakens your defenses over years, and why some people need long-term monitoring after starting certain treatments. You’ll see real cases, real tests, and real advice—not guesswork. If you’ve ever wondered why you’re always the one sick at work, this is where answers start.