Frequently called ‘just-in-case’, ‘rainbow draws’ or simply ‘extra tubes’, blood collected before tests are ordered is frequently unused and ultimately discarded. This represents a waste of laboratory resources and a challenge for specimen management. Excessive phlebotomy is a recognized contributor to iatrogenic anemia, which is linked to worsened patient outcomes. For more information:
Gray A. Drawing extra blood tubes in the ED. Med Lab Observer [Internet]. 2012.
Humble RM, Hounkponou HG, Krasowski MD. The “Rainbow” of extra blood tubes – Useful or wasteful practise? JAMA Int Med 2017:177(1):128-9. PMID: 27820611.
Loh TP, Saw S, Sethi SK. Extra blood tubes – an affordable excess? Clin Chim Acta 2010:411:1544-5. PMID: 20542023.
Snozek CLH, Hernandez JS, Traub SJ. “Rainbow Draws” in the emergency department: clinical utility and staff perceptions. J Appl Lab Med 2019:4(2);229-234. PMID: 31639668.