Screening & randomisation

More details on the screening and randomisation processes for T4P are outlined here:

Anyone who is performing screening, eligibility and/or randomisation tasks for T4P must be trial trained and listed on the local T4P training log.

  • Doctors, nurses and AHPs (including research nurses/practitioners)
  • Appropriately trained and delegated by the PI
  • Listed on the Delegation and Training Logs and have GCP training


  • Other appropriate clinical staff who will solely be involved in screening and randomisation
  • These staff members should be provided with trial-specific training to carry out these tasks and recorded on the Training Log

They do not need GCP training

A doctor, nurse, or clinical practitioner, as long as they are appropriately qualified, and have undergone study training as documented on the training log.

There must still be oversight by a medically qualified doctor. I.e., if the person confirming eligibility is not a doctor, they must receive agreement from the doctor responsible for the patient’s care that the patient is suitable to be entered into the trial. The doctor responsible for the patient’s care does not necessarily need to be trial trained.

  1. Adult (aged ≥18 years)
  2. Accepted for admission or admitted to a participating critical care unit
  3. Platelet count <50×109/L
  4. Planned to undergo a specified* low bleeding risk invasive procedure OR platelet transfusion being considered for an ‘other’ procedure

*Specified low bleeding risk invasive procedures include the following:

  • Central venous vascular catheter insertion (including vascular access for renal replacement therapy)
  • Paracentesis/superficial abdominal fluid collection drainage
  • Pleural aspiration

 ‘Other’ procedures may be included if the clinician deems these to be a low bleeding risk invasive procedure and a platelet transfusion is being considered for the procedure.

These include, but are not limited to, the following:

  • Arterial catheter insertion
  • Arterial or central venous catheter removal
  • Pleural drain
  • Interventional radiology (as defined by Society of Interventional Radiology guidelines)
  • Bronchoscopy with or without lavage
  • Wound dressing changes
  • Surgical procedures where the clinical team agree risk of bleeding is low, e.g. re-look laparotomy, or wound closure
  1. Ongoing major haemorrhage requiring blood products and/or surgical/radiological intervention†
  2. Intracranial haemorrhage within prior 72 hours†
  3. Contra-indication to platelet transfusion (such as thrombotic microangiopathies; heparin-induced thrombocytopaenia; immune thrombocytopaenia; congenital platelet function defects)
  4. Acute promyelocytic leukaemia (APML)
  5. Advance decision refusing blood/blood component transfusions (e.g., Jehovah’s Witnesses)
  6. Death perceived as imminent or admission for palliation.
  7. Previously randomised into T4P
  8. Fulfilled all the inclusion criteria and none of the other exclusion criteria ≥ 72 hours

†Exclusion criteria no. 1 and 2 are dynamic, and if resolved, the patient may be reconsidered for the trial.

Patients undergoing procedures not eligible for randomisation will remain available for inclusion where subsequent eligible procedures occur, provided it is not more than 72 hours after they initially fulfilled all eligibility criteria.

Patients are no longer eligible for T4P if they initially became eligible more than 72 hours ago.

For example, a patient may have a platelet transfusion for a low bleeding risk procedure whilst their platelet count was less than 50×109/L, but they were not randomised before this procedure despite meeting ALL eligibility criteria.

However, although the patient was not randomised prior to this procedure, they can still be randomised within the next 72 hours, providing they still meet the eligibility criteria again (which includes needing another low bleeding risk invasive procedure) and that they are randomised immediately prior to that low bleeding risk invasive procedure.

If the patient does not require another low bleeding risk invasive procedure in the 72-hour timeframe from initially meeting eligibility, they now meet exclusion criterion no. 8 and are no longer eligible for T4P.

Slides for extra training can be found here.

Please complete a paper randomisation form which can be found here.

Sealed Envelope is a 24/7 web-based randomisation service which we will be using for T4P.

You can find the website here and can use either an individual account or generic team sign-in.

Please find a step-by-step guide here for how to randomise using Sealed Envelope.

More detailed training slides for screening and randomisation can be found here.