Science Sep 27, 2024

Preparing For Your Blood Draw

Your blood panel is the foundation everything else at Keyspan is built on — your action plan, your supplement recommendations, and what Kai can tell you about your body specifically rather than about people in general.

Which means it's worth a few days of small adjustments to make sure what we measure is actually you, and not what you happened to do the day before.

Here's how to prepare.

The short version

When	What to do
2 days before	Pause all supplements, including your Keyspan pack. Skip intense exercise.
1 day before	No alcohol.
The night before	Start your 12-hour fast. Water only — no coffee.
The morning of	Water only. Keep drinking it. Bring a photo ID if you're going to a lab.
Throughout	Keep taking prescribed medications exactly as prescribed.

Everything below is the same list with the reasoning attached — worth reading once, because prep is much easier to follow when you know what each step is protecting.

2 days before your draw

1. Pause all supplements — including your Keyspan pack

What to do: Stop taking supplements 48 hours before your test. That includes your Keyspan supplements.

Why: Supplements are designed to change biomarker levels, and over 48 hours some of that acute influence clears. We want to see where your body actually sits, not where this morning's stack put it. This is also how we find out whether your pack is doing its job — if your levels have genuinely improved between panels, that's real change rather than a reading taken an hour after you took the thing we're measuring.

If you're unsure whether something counts as a supplement, treat it as one and pause it.

2. Skip intense exercise

What to do: Avoid hard training for 2 days before your test.

Why: A demanding session temporarily shifts several markers, and those shifts can make a completely normal result look abnormal. Walking, easy movement, stretching, and ordinary daily activity are all fine. It's the sessions that leave you sore or genuinely wrecked that distort the picture.

1 day before your draw

3. Skip the alcohol

What to do: No alcohol for 24 hours before your test.

Why: Alcohol interferes with several of the markers on your panel, and the effect lasts well beyond the point where you feel back to normal.

The night before

4. Start your 12-hour fast — water only

What to do: Fast for at least 12 hours before your appointment. Water only, and that means no coffee — including black coffee.

Why: Fasting keeps your last meal from moving your numbers, so what you see is your actual baseline rather than your dinner.

Coffee is the one people ask about most, so it's worth being specific. Black coffee is nearly calorie-free, but it isn't inert. Caffeine temporarily affects insulin sensitivity and raises cortisol, and both insulin and cortisol are on your Keyspan panel. Coffee is also a mild diuretic, which works directly against the hydration that makes your draw quick and comfortable.

Save it for afterwards. It'll taste better.

Working out your cutoff: count back 12 hours from your appointment time. An 8:00 AM appointment means your last food is at 8:00 PM the night before. A 10:00 AM appointment means 10:00 PM. Plan dinner accordingly and you won't have to think about it again.

5. Keep drinking water

What to do: Drink plenty of water through your fasting window and right up until your draw.

Why: Hydration makes your veins easier to find, which makes the draw faster and more comfortable. It also keeps your blood from concentrating in a way that can nudge several readings. This is the one prep step that helps both your results and your experience, and it's the one most people underdo.

Throughout: keep taking your prescriptions

What to do: Continue taking any prescribed medications exactly as prescribed, unless the doctor who prescribed them tells you otherwise.

Why: Your prescriptions are keeping something steady, and a blood test is not a reason to interrupt that. Never pause a prescription for a lab draw on your own — if you think one might affect your results, ask your prescribing provider first, not us.

Note that this is different from the supplement guidance above. Supplements pause; prescriptions don't.

The morning of your draw

Water only. Keep drinking it.
No coffee, no tea, nothing with calories.
Take your prescriptions as normal.
Wear a top with sleeves that push up easily above the elbow.
Going to a lab? Bring a photo ID. Your order is already on file — check in at the front desk and give your name.
At-home draw? Have a well-lit spot ready with somewhere to sit and a surface for your phlebotomist to work on.

The draw itself takes about five minutes.

What if you booked at short notice?

Some of this prep needs a two-day runway, and sometimes an appointment can't wait that long. If your draw is sooner than that, don't cancel — just do what you can.

Booked less than 48 hours out? The supplement pause and the exercise window have already passed, so focus on what's still ahead of you: the 12-hour fast and the 24-hour alcohol window. Those two carry the most weight anyway. Some of your results may reflect your last couple of days more than your usual baseline, and it's worth knowing that when you read them.

Booked less than 12 hours out? A full fast isn't possible, and fasting has the single biggest effect on your results of anything on this list. If you can move your appointment, we'd genuinely suggest it — a rushed draw is one you may end up wanting to repeat. If you can't, eat nothing between now and your appointment and drink water only.

Rescheduling

In-lab appointments: Change or cancel whenever you like, right up to your appointment. There's no charge and no limit. If a week comes along where you can't prep properly, moving your draw is almost always the better call — we'd rather you got clean results a week later than compromised results on schedule.

At-home appointments: Please reschedule at least 24 hours before your scheduled time, since a phlebotomist is being dispatched to you. Use the rescheduling link in your appointment email or calendar invite. There can be a $99 reschedule fee applied if done in less than 24 hours.

After your draw

Eat something. If there's nowhere convenient near your lab, bring a snack with you. If you're someone who gets lightheaded after a blood draw, sit for a few minutes before you drive.

Coffee, supplements, and normal training are all back on the table the moment you're done.

Results usually take 4 to 7 days. We'll let you know as soon as they land, and Kai will walk you through what they mean for you specifically — not just which numbers fell outside a reference range, but what's worth acting on and in what order.

Need help?

If you have questions about any of this, contact your Keyspan health coach or reach our support team at support@getkeyspan.com

One request: if you weren't able to follow part of the prep — you had a coffee, you forgot and took your supplements, you trained hard the day before — tell us. It isn't a problem, and it isn't a reason to skip your appointment. It just helps us read your results correctly, and that's the whole point.