Routine clotting studies -a bloody waste of resources?

Joanne BratchellLead Nurse Pre-operative AssessmentSt George’s Hospital, Tooting

Antonia Field-Smith Specialist Registrar in Haematology

Defensive?

Persuasion?

The problem with clotting screens

Do not predict bleeding risk in most patients

Do not accurately reflect in vivo haemostatic response

Designed to detect factor deficiencies in patients with high pre-test probability of bleeding

Low sensitivity and specificity

The clotting cascade

Causes of abnormal clotting screens

Shortened clotting times slow or difficult

venepuncture incorrect volume of

blood in tube inadequate mixing usually not clinically

significant ?increased

thrombotic risk

Prolonged clotting times flawed collection or

prolonged storage anticoagulants heparin

contamination coagulation factor

deficiency inherited acquired

lupus anticoagulant factor inhibitor

Background

Lack of clear NICE guidelines meant clotting screens routinely ordered pre-operatively in our Trust

All evidence available concludes that routine testing in apparently healthy or asymptomatic individuals is unlikely to lead to little if any benefit (Munro et al 1997, ASA 2002, NICE 2003, British Committee Standards in Haematology 2008 )

Aims and Objectives

To determine whether preoperative clotting screens were requested in adherence with Trust guidelines

To determine whether abnormal clotting results affect the clinical management or surgical outcome of elective surgical patients

Methodology

Data collected over 2 week period Included all elective surgery

patients over 18 years of age from 4 care groups attending pre-op clinic

Staff asked to record whether clotting screen requested and why indicated

Results

120/181 (66.2%) patients had clotting screens requested

Only 16 (13.3%) studies requested in line with guidelines

78 (65%) ordered routinely 23/120 (19%) prolonged abnormal

clotting screens

Abnormal results

Causes of abnormal clotting screens in 34 patients out of 120 with clotting screens requested

8

7412

1

11

Warfarin

Borderline raised APTR

APTR >1.3

Factor XI deficiency

Borderline raised INR

Borderline raised TT

Shortened APTR

Outcome

No change to clinical management in patients with abnormal clotting results

Only 5 out of 14 patients with unexplained prolonged clotting times had repeat testing

Perioperative bleeding in 5 patients with prolonged clotting screens All major orthopaedic cases – likely surgical

bleeding

The best way forward?

Bleeding history

Questions No Yes Details

Family history Do you have any family history of bleeding disorders, especially parents and siblings?

Prolonged bleeding post-op

Have you ever had any unexplained prolonged bleeding after surgery, dental extractions or childbirth and/or subsequently required a blood transfusion?

Nosebleeds Do you have frequent (at least once a month) gushing nosebleeds that do not respond to pressure after 15 mins and/or require a visit to A&E?

Revised guidelines

Clotting screen

All abnormal results should be repeated

Discuss any persistently abnormal results with Haematology registrar

Positive bleeding history• Family history of bleeding disorder• Prolonged post-op bleeding• Nosebleeds

Refer to haematology

Liver disease

Renal disease eGFR < 30 or on dialysis

Known bleeding disorder Liaise with Haemophilia team

On anticoagulants Not at pre-op visit

Jehovah’s witnesses

Recommendations for practice

Stop ordering routine clotting studies! If positive bleeding history, refer to

haematology All abnormal results should be repeated Refer to haematologist if result remains

abnormal Stop ordering clotting test for warfarin pts

at pre-op visit

Financial implications

Clotting studies at St George’s cost £3.51 a time representing £ thousands per year

In average year, approx £10,500 on pre-op clotting tests

Potential saving of £9000 by adhering to guidelines

Conclusion

Routine clotting studies have no value in the management of elective surgery patients

Limited value to patients and significant cost implications to the Trust

Clotting studies should only be ordered when indicated by medical history or local guidelines

Thank you

Any questions?