Ong et al used multivariate analysis to identify preoperative factors in patients who needed red blood cell transfusion either during or following a surgical procedure. This can help the surgeon decide what blood orders are appropriate for a patient.

Parameters identified as associated with blood transfusion in surgical patients:

(1) preoperative hemoglobin < 12 g/dL

(2) age > 60 years

(3) operation classed as type 5-7 in Surgical Tables



• The Surgical Tables refers to the Singapore Ministry of Health's surgical operation fee tables, which classifies cases from 1 to 7, with 1 being minor procedures and 7 the most extensive. All operations classed 5 or higher are major surgical procedures.

• In the implementation, I've substituted expected blood loss (none, low, moderate and high) for operation class, since major surgical procedures will usually have moderate or high blood loss.


number of risk factors for transfusion =

= SUM(number of parameters present)



• minimum number of transfusion risk factors: 0

• maximum number of transfusion risk factors: 3


Risk of Transfusion

Appropriate Preoperative Blood Order

very low or low



type and screen


type and crossmatch


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