Order of draw: quick reference

A short summary of the order of draw and why it matters.

A commonly used order

Blood cultures, then citrate (coagulation), then serum tubes, then heparin, then EDTA, then fluoride oxalate, then anything else. Follow the order your receiving laboratory specifies, and ask the laboratory or your tube supplier for a chart that matches the tubes you use.

Why the order matters

Additives can carry from one tube to the next. EDTA carried into a biochemistry tube, for example, can affect calcium and potassium results, and heparin can affect coagulation results.

Only one tube?

Check local guidance on whether a discard tube is needed before a coagulation sample, particularly when using a butterfly set.

General information only. Your receiving laboratory's handbook and your employer's procedures take precedence.

More reference

Blood tube colours and additives

What the common blood tube additives are for, and why the cap colour is only a guide.

Reference ranges

Why we do not publish reference ranges, and why collection technique matters for them.

Reading a blood test request

What to check on a request before you take blood.

Lola Dispatch is invitation-only

Lola Dispatch offers mobile blood draw jobs to approved phlebotomists. We add phlebotomists by invitation.

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