Coagulation tests are useful to screen for some bleeding disorders in those with a suggestive bleeding history but alone are poorly predictive in assessing risk of bleeding pre procedure. An abnormal coagulation screen does not necessarily increase the risk of bleeding and a normal coagulation screen does not rule out a bleeding disorder.

Indications for coagulation screens include:

• Before starting anticoagulation
• When investigating thrombocytopenia
• To look for a lupus anticoagulant
• Monitor anti-vitamin K anticoagulant (only request specific assay i.e. INR for warfarin)
• In the presence of a bleeding history
• Monitor severity of liver disease
• In patients with liver disease and high ASA grade pre surgery

A common cause of a prolonged APTT is the presence of an antibody which interferes with the assay. The commonest example is a lupus anticoagulant (LA). When a prolonged APTT is found, the lab will often automatically do further tests to try to work out the cause. The confirmatory test for a LA is the DRVVT. A LA is a type of anti-phospholipid antibody and is often not clinically significant but can be associated with anti-phospholipid syndrome (APS) and other autoimmune diseases. Anti-cardiolipin and anti-beta-2 glycoprotein-1 antibodies are also seen in patients with APS. Anti-phospholipid antibodies are detectable in up to 5% of the normal population and can be a transient phenomenon and therefore we may advise to repeat after three months to ensure resolution. However this is only indicated in patients with symptoms suggestive of APS (pregnancy morbidity, thrombosis, neurological symptoms, thrombocytopenia etc.). In asymptomatic patients where a LA has been picked up coincidentally, no further tests are indicated.

If the coagulation screen is unexpectedly abnormal suggest repeat in first instance as pre-analytical variables heavily affect results.

Look at older results – is this a new problem? Ensure sample not taken from a line or the patient is on an anticoagulant. Ask about personal and family history of bleeding:

• Bleeding associated with trauma or surgical challenges including dental procedures – was there abnormal bleeding, was blood transfusion required, did the patient need to have additional intervention to secure haemostasis?
• Heavy menstrual bleeding from menarche
• Undue bleeding around pregnancy or delivery
• Bruising or excess bleeding in minor injuries
• Spontaneous bleeding – gastrointestinal, joint/muscle bleeds, intracranial haemorrhage, epistaxis

If there is easy bruising look at medications and ask about alcohol history. In addition to anticoagulants, NSAIDS and anti-platelet agents, antidepressants may also cause bruising. Rarely if a patient is malnourished vitamin C deficiency causes bruising.

Bruising is common in elderly patients due to lack of skin tone and also in patients taking long-term steroids. Examine for lymphadenopathy or splenomegaly and look for signs of liver disease, hypermobility or hypothyroidism. Ask about a family history of bleeding disorder. Please bear in mind the risk of non-accidental injury and abuse if unexplained bruising.

Suggested investigations

• Full blood count and blood film (urgent)
• Repeat coagulation screen
• Renal and liver function
• TSH
• Urinalysis if a petechial rash
• Further investigations may have already been reflexed from the laboratory
  e.g. investigation for an antibody such as lupus anticoagulant or factor assays

This depends on why the test was done and the results. If there is clinical concern about a bleeding disorder due to a suggestive personal or family history we would suggest referral even if the coagulation screen is normal. If there is an alternative cause of the abnormal coagulation e.g. liver disease then suggest discussion with the relevant specialty. If uncertain then please discuss via Clinical Dialogue.

Sudden onset bruising may be the first sign of thrombocytopenia.  If this is suspected then arrange an urgent full blood count and coagulation screen.

Patients frequently complain of ‘easy bruising’. This is more common in the elderly due to reduction in skin tone and may be exacerbated by steroid therapy and anti- platelet or anticoagulant medication. If the bruising is localised to one area (e.g. legs), if there are no other bleeding symptoms (especially if previous unremarkable surgical challenges), if the bruising is a recent phenomenon and the full blood count and coagulation screen is normal then the likelihood of finding an underlying inherited bleeding disorder is slim.