Coagulation, Laboratory and Monitoring
Laboratory Tests RCC testing Laboratory tests Consensus Grade 12.1 aPPT, PT and INR have little relevance in acute ongoing haemorrhage. Yes N/A Traditional tests such as aPPT, PT and INR have been standardised for the monitoring of anticoagulants and are designed to diagnose and manage factor deficiencies such as haemophilia. Standardisation within laboratories has made the results v
Laboratory tests
| Consensus | Grade | ||
| 12.1 | aPPT, PT and INR have little relevance in acute ongoing haemorrhage. | Yes | N/A |
Traditional tests such as aPPT, PT and INR have been standardised for the monitoring of anticoagulants and are designed to diagnose and manage factor deficiencies such as haemophilia. Standardisation within laboratories has made the results very reliable.
The PT and aPTT were not designed to monitor coagulation deficiencies during haemorrhage and suggested INR and aPTT ratios or triggers, which are widely quoted to guide coagulation product replacement, are based on small historic studies that have little relevance today. Slow turnaround time also means that the results do not reflect the dynamic clinical situation during ongoing haemorrhage.57
RCC Testing
| Consensus | Grade | ||
| 13.1 | The use of validated POC tests is a more relevant reflection of coagulation status and is preferred. | Yes | B |
| 13.2 | Patients at high risk (> 10% risk of thrombotic events per year) of thrombosis should be considered for bridging anticoagulation, or in the following circumstances:3-5 - Embolic stroke or systemic embolic event within the previous three months. - Mechanical mitral valve. - Mechanical aortic valve and additional stroke risk factors. - Atrial fibrillation and very high risk of stroke (e.g. CHADS2 score of 5 or 6, stroke or systemic embolism within the previous 12 weeks, concomitant rheumatic valvular heart disease with mitral stenosis). - VTE within the previous three months (preoperative and postoperative bridging) - Recent coronary stenting (e.g. within the previous 12 weeks). - Previous thromboembolism during interruption of chronic anticoagulation. |
Yes | B |
| 13.3 | Bridging anticoagulation usually consists of LMWH. | Yes | C |
POC testing has a shorter turnaround time and represents a more global and relevant reflection of coagulation status.58 POC testing is increasingly popular in general and cardiac surgery, trauma units, intensive care and obstetrics. POC testing for Hb concentration is commonly used, such as blood gas analysis or the HemoCue® (Angelholm, Sweden), where both correlate well with laboratory measurements.59 The activated clotting time (ACT) is also well validated and should be used routinely whenever heparin is administered, particularly in cardiac and vascular surgery.
Targeted blood component therapy based on POC testing has been shown to be safe and effective, and decreases blood product usage. However, there are currently no studies that show improved patient outcome compared with standard treatment.34
At the current time, there are two commercially available semi-automated viscoelastic machines that use similar technology: thromboelastometry (ROTEM, TEM International, Munich, Germany) and thromboelastography (TEG, Haemonetics Corp, Braintree, MA, USA). One manufacturer cannot be recommended above the other.
There are no universal algorithms across the specialities, and local protocols are required based on institutional procedures. There is limited interchangeability between TEG and ROTEM, and development and validation of separate treatment algorithms for the two devices are required.60
There are concerns about standardisation of both assays with poor quality control and assurance and a wide variation in results between centres.61 It is good practice to pair coagulation samples and send a second sample for laboratory-based analysis.
South African Society of Anaesthesiologists (SASA) Guidelines for Patient Blood Management 2020. Confirmed as current version on the SASA website as of November 2024.