Spring Bloodwork: Which Labs to Actually Ask For at Your Physical

Your physical is on the calendar. Fifteen minutes, maybe twenty. A blood pressure cuff, a few questions about how you're sleeping, and whatever panel the system orders by default.

Three days later a message lands in the portal. Everything looks normal.

And you're sitting there with the same crash at four in the afternoon, the same hair in the drain, the same middle that showed up sometime in January.

You're not imagining it, and your doctor isn't missing something obvious. A standard panel is built to catch disease. It isn't built to describe how you're aging.

Those are two different jobs. Let's talk about what the default draw measures, what it misses, and what to ask for before you go.

Why “normal” is a lower bar than you think

A reference range is not a health target. It's a statistical description of roughly the middle 95 percent of the people who got tested. It tells you that you resemble the population.

The population is not doing well.

So a number can climb steadily through its range for a decade, and every year you'll get the same word back. Normal. Nothing was wrong on any of those days. Something was clearly moving.

Here's what genuinely frustrates me about that. The trend is the most useful thing in your chart, and it's the thing most likely to go unread.

Whether your value is in range is the least interesting thing about it. Where does it sit inside that range, and which direction did it move since last year?

Why March is a useful month to draw

This isn't about spring cleaning your bloodwork. It's about a few markers that read differently at the end of winter.

Vitamin D is the clearest one. Across the northern half of the country, the winter sun sits low enough that your skin makes very little of it from roughly October through March. How much you make varies with latitude, season, time of day, and your skin tone. This is a pattern, not a line on a map. Whatever you had in September has been drawing down all winter.

So a March draw shows you your floor. That's the number worth knowing. An August result flatters you.

The rest of the winter shows up too. Your training falls off when it's dark at four thirty. Your drinking goes up through the holidays and doesn't always come back down. Fasting glucose, triglycerides and blood pressure all reflect the season you just had. If you want an honest read on it, take it now.

The labs to ask for

Your standard draw almost certainly includes a CBC, a comprehensive metabolic panel, and a lipid panel. Those are worth having. They're just not enough to plan from.

So what's missing?

Bring this list to your appointment. Ask which ones your insurance covers, and what it costs to add the rest.

For metabolic trajectory:

• Fasting insulin, drawn alongside fasting glucose
• Hemoglobin A1c
• ApoB
• Lp(a), once in your life
• Triglycerides and HDL, usually already on your lipid panel

For nutrient status and background inflammation:

• 25-hydroxyvitamin D
• Ferritin, not just hemoglobin
• B12
• RBC magnesium where available, serum magnesium if not
• TSH with free T4
• hs-CRP

That's eleven lines added to a requisition. Not a specialist referral, not a boutique panel. Eleven lines.

The four that change what I do

Fasting insulin moves first. Your pancreas compensates quietly for years before glucose budges. By the time it looks off, the process is well underway. A1c gives you the average of roughly the last three months. Fasting insulin tells you what it cost your body to hold that average. In my practice, high insulin often travels with hunger two hours after eating, an afternoon wall, and a waist that thickens while the scale sits still. Those symptoms are non-specific. They confirm nothing without the draw.

ApoB counts particles. Your standard LDL number estimates how much cholesterol is being carried around. ApoB counts how many particles are doing the carrying, because each one carries exactly one ApoB. It's the difference between weighing the freight and counting the trucks. The trucks are what end up in the artery wall. Lp(a) is a separate, largely inherited particle, and you only need it measured once, but knowing it changes how seriously everything else gets treated.

Ferritin empties before hemoglobin falls. Ferritin reflects your iron stores. Your body spends those stores down to keep hemoglobin looking normal, which means you can be told you aren't anemic while your reserves are nearly gone. Low stores can show up as hair shedding, cold hands, being winded on stairs, and flat sets. That picture fits several other explanations, and it confirms nothing on its own. This matters most if you still menstruate, if you're on a GLP-1, or if you rarely eat red meat.

Vitamin D is the one you can move most by June. It isn't a cure for anything, and it gets oversold. But you need it to absorb calcium, to build bone, and for your muscles to work properly. The doses I see used in practice usually fall in the range of 2,000 to 4,000 IU daily, and 4,000 IU sits at the tolerable upper limit for adults. Which dose fits your number, and when it gets rechecked, is your physician's call.

How to get a draw worth reading

1. Call the office a week ahead. Ask for the additions to be put on the requisition before you arrive. A standing order is far easier to edit in advance than to negotiate in the exam room.
2. Fast properly. Eight to twelve hours, water only. Fasting insulin and triglycerides are the two that punish a splash of cream in your coffee.
3. Leave two days between hard training and the draw. A heavy session or a long run can temporarily raise hs-CRP and liver enzymes. Otherwise you spend six weeks chasing a number that was just Saturday.
4. Wait two weeks after an illness. Ferritin and hs-CRP both rise with infection. A ferritin drawn at the tail end of a March cold can look reassuring while your stores are low.

What's mine and what's your doctor's

I read labs. I don't diagnose and I don't prescribe, and that line matters here, because knowing which side of it your result falls on is half of what makes a panel useful.

These belong to your physician. A TSH or free T4 outside the range. A ferritin low enough that someone should ask where the iron is going. An A1c in the diabetic range. A high Lp(a). Anything flagged for follow-up, and anything involving chest symptoms, shortness of breath, or weight loss you didn't intend. Ask for the repeat draw or the referral. Don't try to manage those with groceries.

A ferritin that reads normal while you feel the way I described above belongs on this side too. Your physician gets to ask where the iron is going before anyone calls it a grocery problem.

These are usually a plate, a barbell and a sleep window. Insulin drifting upward inside the range. Vitamin D sitting at the bottom of the range in March. Triglycerides climbing while HDL slides. Protein intake that never scaled with what you ask your body to do. Magnesium and B12 intake that never kept pace with the last ten years.

Here's the catch: you can have both. Most of the people I work with do. A thyroid that needs a physician and a protein intake that needs a plan are not competing explanations for how you feel. They're one appointment, split two ways.

What you're actually building

One year of labs is a snapshot. Three years, drawn in the same month in the same fasting state, is a trajectory. Your trajectory is what tells you whether any of this is working.

So ask for the actual PDF, not just the portal summary. Portals change, practices change, and a result you can't retrieve might as well not exist. Keep them in one folder with the date in the file name. That folder will be worth more to you at 70 than any single number is today.

Then measure the rest. What you can lift, how you recover, how you sleep, whether the groceries come in one trip. Labs describe your interior. Function describes your life.

You don't need all eleven this week. Pick one thing: call the office and ask for fasting insulin, ferritin and 25-hydroxyvitamin D to be added before your appointment. Three lines. One phone call.

And if you'd rather not read your results alone, and you want a plan for the next thirty years instead of the next thirty days, that's the work I do. A free 30-minute strategy call is a good place to start.

Your bloodwork has been telling you a story every year. The question is whether anyone has been reading it.