Table 4.
Further analysis (stage 2) for diagnostic assessment of thrombocytopathies/-penias (depending on the results of the first stage investigations)
| Test | Assessment/detection | Material |
|---|---|---|
| Repetition of platelet aggregation from stage 1 (see table 1) | verification of results; if results are suggestive, perform platelet granule secretion assay | PRP from citrated blood |
| Flow cytometry | ||
| Platelet receptors: e.g. GP-IIb/IIIa, GP-Ib/XI/V | reduced/absent GP-IIb/IIIa receptor (Glanzmann thrombasthenia) or GP-Ib/IX/V receptor (Bernard-Soulier syndrome) | PRP from citrated blood; determination of receptor count is possible in 1- to |
| Functional PAC-1 or fibrinogen binding to GP-IIb/IIIa | reduced fibrinogen binding of GP-IIb/IIIa | 2-days-old blood samples given that a healthy controls sample was also sent to the laboratory; functional measurements should be performed within 3 h after PRP preparation |
| Activation marker: | activation- and/or secretion-deficiency | |
| CD62 (receptor of α-granules) | ||
| CD63 (receptor of 8-granules) | ||
| Mepacrine staining | reduced/absent δ-granules | |
| Signal transduction: | phosphorylation defects | |
| VASP | ||
| MAP kinase | ||
| Other procedures | ||
| Platelet adhesion (microscopically) | adhesion to different surfaces (siliconized glass, collagen, fibrinogen, subendothelial matrix); defects in Glanzmann thrombasthenia, Bernard-Soulier syndrome, different giant platelets thrombocytopathies | PRP from citrated blood |
| Platelet spreading (microscopically) | size of platelets | PRP from citrated blood |
| Volume distribution (microscopically, cell counter), blood smear | giant platelets (Bernard-Soulier syndrome, May-Hegglin anomaly), leukocytes inclusions (May-Hegglin anomaly and related diseases) | PRP from citrated blood, EDTA-anticoagulated whole blood |
| Plasma exchange test, MAIPA (monoclonal antibody immobilization of platelet antigens test) | detection of platelet antibodies in acquired autoantibody induced thrombocytopenia/thrombocytopathy | PRP from citrated blood |
| Platelet granule-secretion assay, luminometry (firefly method), ELIS A (serotonin detection) | ATP content and ATP secretion, serotonin-content (δ-storage pool disease) | PRP from citrated blood |
| ELISA (PF4, PDGF, P-thromboglobulin) | PF4-, PDGF-, β-thromboglobulin-content (α-storage pool disease) | |
| Electron microscopy of platelets | α- or δ-storage pool defect; particularly δ-granules are presentable with easy preparation technique | PRP from citrated blood |