The 5 Labs Your Doctor Should Be Checking (But Might Not Explain)
The journey to better health doesn't start with a dramatic diet overhaul or an intense workout program.
It starts with understanding what's actually happening inside your body. And that means looking at your lab trends, not just whether numbers are flagged as "normal" or "abnormal."
Most people get their labs done once a year. Their doctor glances at the results during a rushed appointment. "Everything looks good!" And they leave with no real understanding of what those numbers mean or whether they're moving in the right direction.
Here's what happens when you start paying attention to lab trends: you catch problems early, when they're easier to address. You see patterns that explain why you feel the way you do. You have data to guide your decisions instead of just guessing.
A client came to me recently with a stack of lab results. "My doctor said everything looks normal. But I feel terrible. I'm exhausted, my weight is creeping up, and I can't think straight. If my labs are fine, what's wrong with me?"
I looked at her results. Her doctor wasn't wrong that nothing was critically high. But several numbers were trending in the wrong direction. And more importantly, her doctor never explained what any of them actually meant or why they mattered together.
This happens all the time.
Here's what I want you to know: you don't need to be a medical expert to understand your own labs. But you do need to know which numbers matter most and what they're actually telling you.
These are the 5 labs I look at closely with every client. If you have an upcoming appointment or recent labs, pay attention to these.
1. Hemoglobin A1C (And Why Fasting Glucose Isn't Enough)
What it measures: Your average blood sugar over the past 2 to 3 months.
Why it matters: Fasting glucose only shows what's happening after you haven't eaten for 8 to 12 hours. It misses what's happening after meals. A1C gives you the bigger picture. You can have a "normal" fasting glucose of 95 mg/dL and still have an A1C of 5.8% (prediabetes range) if your blood sugar spikes high after eating.
What to look for:
Below 5.7%: Normal
5.7% to 6.4%: Prediabetes
6.5% or higher: Diabetes
But here's what most doctors don't tell you: even within the "normal" range, higher numbers predict future risk. An A1C of 5.6% isn't the same as 5.0%. If your A1C is trending upward over time, that's information worth paying attention to, even if you're still technically "normal."
I've had clients whose A1C went from 5.2% to 5.5% over two years. Their doctor said "still normal, nothing to worry about." But that upward trend matters. It's a signal that something's shifting metabolically. Catching it early means you can make changes before you're dealing with prediabetes or diabetes.
2. Lipid Panel (But Not Just Total Cholesterol)
What it measures: Your cholesterol breakdown including LDL, HDL, triglycerides, and total cholesterol.
Why it matters: Most people only hear "your cholesterol is high" and think that's the whole story. But the ratios between these numbers matter more than any single value.
What to look for:
Triglycerides: Below 150 mg/dL is standard, but I like to see below 100 mg/dL. High triglycerides are often a sign of insulin resistance, too many refined carbs, or excess alcohol intake. They're also a strong predictor of heart disease risk.
HDL cholesterol: This is your "good" cholesterol. You want this higher. Below 40 mg/dL for men or below 50 mg/dL for women is too low. Higher HDL protects against heart disease.
LDL cholesterol: This is your "bad" cholesterol. Guidelines say below 100 mg/dL is optimal, but context matters. What really matters is the type of LDL particles (small, dense particles are more problematic than large, fluffy ones) and your overall cardiovascular risk factors.
Triglyceride to HDL ratio: Divide your triglycerides by your HDL. You want this ratio below 2. If it's above 3, that's a red flag for insulin resistance even if your fasting glucose looks fine. This is one of the best early indicators of metabolic dysfunction.
Example: Triglycerides of 120 divided by HDL of 60 equals a ratio of 2. That's borderline. Triglycerides of 150 divided by HDL of 45 equals a ratio of 3.3. That's concerning and suggests insulin resistance is brewing.
3. Thyroid Panel (TSH Alone Isn't Enough)
What it measures: How well your thyroid is functioning.
Why it matters: Your thyroid controls metabolism, energy, weight, mood, and more. When it's off, everything feels harder. But most doctors only check TSH (thyroid stimulating hormone). That's not the full picture.
What to look for:
TSH: The standard range is 0.5 to 5.0 mIU/L, but many people feel terrible when their TSH is above 2.5, even though it's technically "normal." If you're experiencing fatigue, weight gain, hair loss, or cold intolerance and your TSH is above 2.5, it's worth digging deeper.
Free T4 and Free T3: These show the actual thyroid hormones circulating in your body. You can have normal TSH but low T3, which means your body isn't converting thyroid hormone properly. Many doctors won't check these unless TSH is abnormal. Ask for them anyway, especially if you have symptoms.
Thyroid antibodies (TPO and Thyroglobulin): These reveal if your immune system is attacking your thyroid (Hashimoto's thyroiditis). You can have elevated antibodies years before TSH becomes abnormal. Catching this early matters.
I've had multiple clients whose doctors said "your thyroid is fine" based on TSH alone, but when we ran a full panel, we found low T3 or high antibodies. That explained their symptoms and gave us a path forward.
4. Vitamin D
What it measures: Your vitamin D level, which acts more like a hormone than a vitamin.
Why it matters: Vitamin D affects immune function, bone health, mood, insulin sensitivity, and inflammation. Low vitamin D is incredibly common, especially in people who live in northern climates, have darker skin, or spend most of their time indoors.
What to look for:
Below 20 ng/mL: Deficient
20 to 30 ng/mL: Insufficient
30 to 50 ng/mL: Sufficient
Above 50 ng/mL: Optimal for many people
Most labs flag anything above 30 ng/mL as "normal." But research suggests optimal levels for metabolic health, immune function, and mood are closer to 40 to 60 ng/mL. If you're at 32 ng/mL and struggling with energy, mood, or frequent illness, there's room for improvement.
Low vitamin D is linked to insulin resistance, higher risk of Type 2 diabetes, and worse blood sugar control. Correcting a deficiency often improves metabolic markers.
5. High-Sensitivity C-Reactive Protein (hs-CRP)
What it measures: Inflammation in your body.
Why it matters: Chronic inflammation is linked to heart disease, diabetes, autoimmune conditions, and metabolic dysfunction. This test won't tell you where the inflammation is coming from, but it tells you if inflammation is elevated. That's valuable information.
What to look for:
Below 1.0 mg/L: Low risk
1.0 to 3.0 mg/L: Moderate risk
Above 3.0 mg/L: High risk
If your hs-CRP is elevated, it's worth investigating why. Poor diet, lack of sleep, chronic stress, insulin resistance, autoimmune conditions, and infections can all drive inflammation. This test gives you a baseline to track whether your interventions are working.
I use this test with clients who have metabolic issues, autoimmune conditions, or unexplained symptoms. Watching hs-CRP drop as we improve nutrition, sleep, and stress management confirms we're moving in the right direction.
What to Do with This Information
Before your next appointment:
Request a copy of your labs ahead of time. Many healthcare systems let you access results online through patient portals. Don't wait until you're sitting in the exam room to see your numbers for the first time.
During your appointment:
Ask your doctor to explain any numbers that are trending upward or are in the high end of "normal." Just because something isn't flagged as abnormal doesn't mean it's optimal. Ask: "Is this number moving in the right direction compared to last time?" and "What does this number tell us about my metabolic health?"
After your appointment:
Track your labs over time. Create a simple spreadsheet or document where you record key values from each lab draw. Trends matter more than single data points. An A1C that goes from 5.1% to 5.3% to 5.5% over three years is telling you something, even though all three values are "normal."
If your doctor dismisses your concerns:
You're allowed to ask for additional tests. You're allowed to seek a second opinion. You're allowed to advocate for deeper investigation when something feels off. "Everything's normal" isn't a good enough answer when you don't feel normal.
Your health is worth understanding
Your labs are a snapshot of what's happening inside your body. But most people never learn how to read that snapshot. They rely on a rushed doctor to tell them "you're fine" or "you're not fine," without understanding what the numbers actually mean.
You don't need a medical degree to be informed about your own health. You just need to know which numbers matter, what they're telling you, and what questions to ask.
These 5 labs give you insight into blood sugar regulation, cardiovascular risk, thyroid function, inflammation, and overall metabolic health. If you're getting labs done this month, make sure these are included. And if your doctor isn't checking all of them, ask why not.
Need help interpreting your labs or creating a plan based on what they're showing?
I work with clients to translate lab results into actionable nutrition and lifestyle strategies.
No shame, no restriction, just practical approaches that work. Schedule a discovery call or listen to more on my Blood Sugar Unfiltered podcast.
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