Study	Reason for exclusion
Abels 1991	Participants: Oncology participants Intervention: transfusion rates studied not different triggers.
Almeida 2013	Participants: non‐haematological oncological participants included. An RCT involving adults with cancer who were undergoing abdominal surgery.
Bercovitz 2011	Study design: review
Berger 2012	Study design: Ambidirectional cohort study Intervention: one versus two units studied as opposed to a haemoglobin trigger.
Bruun 2011	Participants: non‐haematological oncological participants included
Carson 2014	A review including RCTs conducting on people with myocardial infarction, brain injury, stroke, or haematological disorders.
Holst 2013	Review
ISRCTN26088319	An RCT involving people with myelodysplastic syndrome.
Lightdale 2012	Study design: cohort study using retrospective control.
Mear 2014	Study design: cohort study using historical control.
NCT00202371	Study withdrawn prior to enrolment
NTR2684	Participants: participants receiving chemotherapy were excluded
Paananen 2009	Study design: no prospective element.
Patil 2013	Study design: no prospective element.
Prescott 2016	Review.
Yakymenko 2015	Participants: non‐haematological oncological participants included. An RCT involving adults with cancer.

RCT = randomised controlled trial