Platelet Satellitism

Morphology:
Platelets clumped around neutrophils.

Found in:
EDTA in vitro induced change of no clinical significance except false low platelet count (in vitro).

Giant Platelets

Morphology:
Platelet larger than a normal red cell.

Found in:
Increased platelet turnover
Myeloproliferative disorders
Myelodysplastic disorders

Large Platelets

Morphology:
Large platelets - larger than one third but less than the size of a red cell.

Found in:
Increased turnover of platelets
Myeloproliferative disorders
Myelodysplastic disorders
May Hegglin anomaly
Grey platelet syndrome
Bernard Soulier

Micro Clots

Morphology:
Fibrin strands, platelets and white cells (in this case - neutrophils) clumped together.

Found in:
In vitro artefact caused by poor venesection technique
Leads to false low counts - can influence white cell, red cell and platelet counts

Platelet Clumping

Morphology:
Small clumps of platelets.

Found in:
In vitro artefact caused by EDTA or cold and leads to false low platelet count
Difficult venesection

Wiskott Aldrich Syndrome

Morphology:
Small platelets.

Found in:
Wiskott Aldrich syndrome

Grey Platelet Syndrome

Morphology:
Platelets appear degranulated.

Found in:
Grey platelet syndrome
Discharge of platelet granules in vivo (cardiopulmonary bypass, hairy cell leukemia)
Discharge of platelet granules in vitro (poor venesection technique)