Most people receive lab results, read "within normal limits" at the top, and file them without looking further. The ones who read the actual numbers often don't know what to do with them.
Here's a plain-language guide to the results that matter most and what to actually pay attention to.
The Reference Range Problem
Lab results show your value alongside a reference range — the range considered normal for the general population. If you're inside the range, you're "normal." If you're outside it, you're "flagged."
That framing misses something important: being inside the normal range and being optimal are not the same thing.
A fasting glucose of 99 mg/dL is technically normal (range: 70–99). It's also just one point below prediabetes. A patient who's been at 82 for three years and is now at 99 has meaningful information in that trend — even though both readings are "normal."
Read your numbers, not just the flags. And read them over time.
The Core Panel: What to Know
Fasting glucose. Blood sugar after an overnight fast. Normal: 70–99 mg/dL. Prediabetes: 100–125. Diabetes: 126+. Watch the direction this number moves year over year, especially if you're in the 90s.
A1C (glycated hemoglobin). A 3-month average of blood sugar levels. More informative than a single fasting glucose reading. Normal: below 5.7%. Prediabetes: 5.7–6.4%. Diabetes: 6.5%+. This is one of the most important numbers to track longitudinally.
LDL cholesterol ("bad" cholesterol). A key cardiovascular risk marker. Optimal for most people: below 100 mg/dL. Higher-risk individuals (diabetes, heart disease history) often target below 70. Context matters here — your LDL in isolation tells a partial story; cardiovascular risk calculators factor in age, blood pressure, smoking, and HDL together.
HDL cholesterol ("good" cholesterol). Higher is better. Below 40 mg/dL (men) or 50 mg/dL (women) is a risk factor. Above 60 is considered protective. HDL tends to improve with exercise and diet quality.
Triglycerides. Fat particles in the blood. Normal: below 150 mg/dL. Elevated triglycerides (200+) are associated with cardiovascular risk and are often responsive to dietary changes — particularly reducing refined carbohydrates and alcohol. This is a number many people can meaningfully improve through lifestyle.
TSH (thyroid stimulating hormone). The primary thyroid screening marker. Normal range varies by lab, but roughly 0.5–4.5 mIU/L. High TSH suggests an underactive thyroid (hypothyroidism); low TSH suggests an overactive thyroid (hyperthyroidism). Both are common and treatable. If you've never had your thyroid checked, ask for it specifically.
Creatinine and eGFR. Kidney function markers. eGFR (estimated glomerular filtration rate) above 60 is generally normal; declining eGFR over years warrants monitoring. Most people don't need to think much about this unless it's flagged — but it's worth knowing what the number means.
CBC (complete blood count). Red blood cells, white blood cells, platelets, hemoglobin. Flagged values here are usually what a provider investigates specifically. The one to know: low hemoglobin or hematocrit can indicate anemia, which commonly presents as fatigue.
What to Do With Your Results
Keep a copy. Every year, save a copy of your full lab panel. Not just the summary — the actual values. A spreadsheet with your key numbers over time gives you and your provider far more information than any single result.
Notice trends before they're flagged. A value that's moved from 75th percentile of normal to 95th percentile of normal over three years is telling you something. Your provider may not flag it; you can still ask about it.
Ask the right question. If you see a value that's new, changed, or that you don't understand: "What does this mean, and is this trending in a direction I should know about?" is a better question than "Is this normal?"
Don't self-diagnose from reference ranges. Lab values exist in context. An elevated white blood cell count could be infection, stress, medication, or many other things. A result outside the normal range is a starting point for a conversation, not a conclusion.
The One Habit Worth Building
Request your labs in a patient portal or by email rather than waiting for a provider to call you. If your provider only calls when something is flagged, you'll never see the gradual trends that matter most.
Your health data belongs to you. Looking at it annually is one of the most useful things you can do with 15 minutes.
Bivvy Health providers review your labs with you during telehealth visits — not just flagged values, but the full picture and what it means for your care. Worth a visit if you've been collecting results without really understanding them.