Laboratory Tests for Initial Workup of Easy Bruising

First-Line Laboratory Tests

The American Academy of Pediatrics recommends a complete blood count (CBC) with platelets and peripheral blood smear to evaluate for thrombocytopenia or abnormal platelet morphology in patients with easy bruising 1, 2
The American Society of Hematology suggests PT/INR to assess the extrinsic coagulation pathway in patients with easy bruising 3, 1
The American Society of Hematology recommends aPTT to evaluate the intrinsic coagulation pathway in patients with easy bruising 3, 1
Fibrinogen level should be assessed for fibrinogen disorders in patients with easy bruising 1

For children with easy bruising, the American Academy of Pediatrics recommends testing for bone metabolism disorders with serum calcium, phosphorus, and alkaline phosphatase 4
For children with easy bruising, the American Academy of Pediatrics suggests testing for bone metabolism disorders with parathyroid hormone and 25-hydroxy-vitamin D 4
For children with easy bruising, the American Academy of Pediatrics recommends testing for bone metabolism disorders with serum copper and ceruloplasmin 4

The American Society of Hematology warns against relying solely on PT and aPTT to rule out bleeding disorders, as this will miss von Willebrand disease and mild platelet function disorders 1, 5
The American Academy of Pediatrics advises against failure to consider non-hematologic causes of easy bruising, such as connective tissue disorders, medication effects, and non-accidental trauma 1
The American Society of Hematology recommends obtaining a thorough bleeding history using a structured assessment tool in patients with easy bruising 3
The American Society of Hematology warns against overlooking the need for specific VWD testing in patients with mucocutaneous bleeding despite normal PT/aPTT 3, 5

The American Society of Hematology recommends von Willebrand factor antigen (VWF:Ag), von Willebrand factor ristocetin cofactor activity (VWF:RCo), and factor VIII coagulant activity (FVIII) testing for initial VWD evaluation, as they can establish the diagnosis and suggest the type and severity of VWD if present 6, 7, 8
Specialized VWD assays should be considered if one or more VWD test results are abnormally low and/or if the ratio of VWF:RCo to VWF:Ag is abnormally low (below 0.5–0.7) 6
VWF multimer analysis should only be performed if initial VWD testing identifies an abnormal result or clinical information suggests a high likelihood of abnormal VWF multimer analysis 6

A complete blood count with platelet count and peripheral blood smear should be performed to detect thrombocytopenia, abnormal platelet morphology, or other hematologic abnormalities in patients presenting with easy bruising. 9

In children who present with easy bruising and have clinical features typical of immune thrombocytopenia, bone‑marrow examination is not required. 9

Add VWD testing (VWF:Ag, VWF:RCo, and Factor VIII activity) when the patient reports easy bruising accompanied by mucocutaneous bleeding such as epistaxis, heavy menstrual bleeding, or gum bleeding. [10][11]
Add VWD testing when there is a personal or family history of excessive bleeding during surgery, dental procedures, or childbirth. 10