| | Test | What it measures | Methodology | Caveats |
| Commonly used | Aggregometry | - Ability of platelets to aggregate in response to several agonists
| - Clinical laboratory
- Whole blood or PRP
| - Labor intensive and requires technical expertise
- Not widely available outside a tertiary center
- May be inaccurate in individuals with moderate to severe thrombocytopenia (platelet count <80,000/microL)
- May be insensitive to secretion disorders
|
| Platelet function analyzer (PFA-100 or PFA-200) | - Closure of a small aperture in the cartridge as a method of assessing platelet function
| - Clinical laboratory
- Cartridge-based system
- Whole blood only
| - Lack of specificity for a platelet function disorder (abnormalities may be caused by other hemostatic disorders)
- Affected by a number of factors including platelet count, hemoglobin, and VWF levels
|
| VerifyNow | - Ability of platelets to aggregate in response to several agonists (a type of automated aggregometry using fibrinogen-coated beads)
| - Point-of-care test
- Cartridge-based system
- Whole blood only
| - Intended for monitoring anti-platelet drugs
- Lacking evidence/not validated for identifying platelet function disorders
|
| Viscoelastic testing, including thromboelastography (TEG) and rotational thromboelastography (ROTEM) | - Global hemostasis, from clot formation, physical properties of the clot, and fibrinolysis
| - Point-of-care test
- Whole blood or PRP
| - Lack of specificity for a platelet function disorder (may be caused by other hemostatic disorders)
- Affected by a number of factors including platelet count and fibrinogen level
|
| Flow cytometry | - Appearance of platelet activation markers after exposure to platelet agonists
- Can also use granule binding dyes to detect granule disorders
| - Specialized laboratory
- Basal or in response to an agonist
- Whole blood or PRP
| - Sensitive
- Quality of samples is important (must be taken without undue activation, may be affected by transportation)
|
| Reserved for special cases or research | Genetic testing | - Pathogenic variants in specific platelet function genes
| - Clinical laboratory
- DNA from cheek swab cells or WBCs from a blood sample
- Single gene or a panel of genes
| - Determines genotype, not function
- May not detect some platelet function disorders
|
| Electron microscopy | - Ultrastructure of platelet granules and other organelles
| - Specialized research laboratory
- Platelets from whole blood or PRP
| - Labor intensive and time-consuming
|
| Microfluidic devices such as the Total thrombus formation analysis system (T-TAS) | - Thrombus formation in whole blood
| - Clinical laboratory
- Whole blood
| - Limited experience to date
|
