Platelet Count
Also known as: Platelets, Thrombocyte Count
Use
Evaluate, diagnose, and/or follow up bleeding disorders, drug-induced thrombocytopenia, idiopathic thrombocytopenia purpura (acute or chronic), disseminated intravascular coagulation, leukemia states, chemotherapeutic management of malignant disease states; investigate purpura, petechiae; evaluate response to platelet transfusions, steroids, or other therapy
Special Instructions
Specimens should be collected using a lavender-top (EDTA) tube. The tube should be inverted 8 to 10 times immediately after collection. Peripheral blood smears prepared at the time of collection can be useful for evaluating platelet aggregation or abnormalities.
Limitations
False low platelet counts may occur due to clumping, platelet satellitism, or fragmented cells. Capillary blood samples may yield lower platelet counts compared to venous samples due to clumping, affecting precision. Small clots in the sample may cause falsely low platelet counts. Certain drugs and conditions can lower platelet counts through various mechanisms, including immunologic responses and marrow suppression. Inaccuracies may arise in the presence of leukemic cells or fragmented blood cells.
Methodology
Automated Analyzer (Hematology)
Biomarkers
LOINC Codes
- 777-3
- 777-3
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Tube fill capacity
Minimum Volume
0.5 mL (500 μL for pediatric microtainer capillary tubes)
Container
Lavender-top (EDTA) tube.
Collection Instructions
Invert tube immediately 8 to 10 times once tube is filled at time of collection.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Hemolysis; clotted specimen; tube not filled with minimum volume; improper labeling; transfer tubes with whole blood; specimen diluted or contaminated with IV fluid; specimen received with plasma removed; specimen collected in any anticoagulant other than EDTA
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 day |
| Refrigerated | 3 days |
| Frozen | Unstable |
Other tests from different labs that may be relevant