What color tube top goes second in a standard "rainbow" lab draw?

Question

A. Lavender

B. Blue

C. Green

D. Yellow

Answer 1

In a standard “rainbow draw”, the typical order of draw and tube colors (following CLSI guidelines) is as follows:

1. Blood culture bottles – sterile specimens first (aerobic/anaerobic)
2. Light blue – sodium citrate (coagulation studies)
3. Red or Gold/SST (tiger-top) – serum tubes (chemistry, serology, blood bank)
4. Green – heparin (chemistry, plasma determinations)
5. Lavender or pink – EDTA (hematology, blood bank)
6. Gray – fluoride/oxalate (glucose, lactate)

So, the second tube in the standard rainbow draw is the light blue top, used for coagulation tests (like PT, PTT, INR).

Answer 2

The correct answer is Blue :)