Overview
Plateletcrit estimates the percentage of blood volume occupied by platelets, usually calculated from count × MPV.
Clinical Importance
As a derived supportive platelet index on some CBC reports
Specimen Requirements
- Specimen: whole blood
- Tube: lavender-top K₂EDTA (preferred) or K₃EDTA
- Anticoagulant: EDTA
- Handling: invert gently 8–10 times immediately after draw; do not shake
- Storage: room temperature preferred for prompt analysis; follow analyzer/manufacturer limits
- Stability: analyze as soon as practical (many CBC parameters are stable for several hours at room temperature; verify local procedure). MPV increases with EDTA storage time. Do not freeze whole blood for CBC.
Analytical Method
Calculated parameter: proportional to platelet count and mean platelet volume (instrument-specific scaling).
Instruments Used
Automated analyzers
- Sysmex XN / XN-L series hematology analyzers
- Beckman Coulter DxH series hematology analyzers
- Abbott Alinity hq / CELL-DYN hematology analyzers
- Siemens Healthineers ADVIA hematology analyzers
- Mindray BC-series hematology analyzers
- HORIBA Yumizen / ABX hematology analyzers
Manual methods
- Not manually measured
Reference Values
Typical adult SI examples below follow widely published international hematology practice (e.g., Dacie and Lewis; Henry's). Always interpret against the method- and demographics-specific interval printed on the patient report (CLSI EP28-A3c). Neonatal, pediatric, pregnancy, and altitude intervals differ.
Method-specific; often a small fraction of a percent of blood volume; use local intervals only.
Interpretation
Common Causes of Increased Results
- Rises with thrombocytosis and/or larger MPV
Common Causes of Decreased Results
- Falls with thrombocytopenia and/or smaller MPV
Clinical Significance
- Adjunct index alongside platelet count where reported
Factors Affecting Results
Pre-analytical
- Any factor affecting platelet count or MPV alters PCT
Analytical
- Inherited error from count and MPV channels
Post-analytical
- Treating PCT as an independent gold-standard measure
Advantages and Limitations
Advantages
- Integrates count and size into one volume-fraction index
Limitations
- Fully dependent on platelet count and MPV validity
- Not universally reported or standardized
Clinical Pearls
If the platelet count is wrong (clumps), PCT is wrong; validate the count first.
References
Authoritative textbooks, guidelines, and reviews supporting this laboratory test reference. Verify reference intervals, critical limits, and method details against institutional protocols and current guideline editions.
Textbooks
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2021.
- Rodak BF, Carr JH. Rodak's Hematology: Clinical Principles and Applications. 6th ed. Elsevier; 2020.
- Hoffbrand AV, Moss PAH, Pettit JE. Essential Haematology. 8th ed. Wiley-Blackwell; 2019.
- McKenzie SB, Williams JL. Clinical Laboratory Hematology. 4th ed. Pearson; 2022.
- Bain BJ, Bates I, Laffan MA. Dacie and Lewis Practical Haematology. 12th ed. Elsevier; 2017.
- Kaushansky K, et al. Williams Hematology. 10th ed. McGraw-Hill; 2021.
CLSI and Professional Guidelines
- Clinical and Laboratory Standards Institute. Validation, Verification, and Quality Assurance of Automated Hematology Analyzers; Approved Standard. CLSI document H26-A2. CLSI; 2010.
- Clinical and Laboratory Standards Institute. Reference Leukocyte (WBC) Differential Count (Proportional) and Evaluation of Instrumental Methods; Approved Standard. CLSI document H20-A2. CLSI; 2007.
- Clinical and Laboratory Standards Institute. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Standard. CLSI document EP28-A3c. CLSI; 2010.
- Clinical and Laboratory Standards Institute. Management of Critical- and Significant-Risk Results. CLSI guideline GP47-Ed1. CLSI; 2015.
Frequently Asked Questions
Common questions about using this Plateletcrit (PCT) laboratory test Medical Laboratory Library reference in Medical Laboratory Science education.
What is the Plateletcrit (PCT) laboratory test reference used for?
This Medical Laboratory Library page summarizes the clinical importance of Plateletcrit (PCT). Review the Clinical Importance section for why the test is ordered in laboratory medicine practice.
Where can I find Plateletcrit (PCT) specimen requirements?
See the Specimen Requirements section on this page for specimen information related to Plateletcrit (PCT). Confirm collection details against your laboratory protocol.
Where are Plateletcrit (PCT) reference values listed?
See the Reference Values section on this Laboratory Library page. Reference ranges can vary by method and population, so verify intervals with your laboratory.
How do I interpret Plateletcrit (PCT) results?
Use the Interpretation section for laboratory interpretation framing, including increased and decreased result patterns when provided. Do not treat educational text as a patient-specific diagnosis.
What analytical method is used for Plateletcrit (PCT)?
See the Analytical Method section for principle and method notes. Method details may differ by instrument and institutional SOP.
Are related laboratory tests linked from Plateletcrit (PCT)?
Yes. The Related Laboratory Tests section lists connected references for continued lookup in the Medical Laboratory Library.
How can I continue learning after reading Plateletcrit (PCT)?
Use Continue learning links on this page for related Academy lessons, medical laboratory quizzes, or laboratory case studies when available for this Hematology topic.
What are the clinical pearls for Plateletcrit (PCT)?
See the Clinical Pearls section for concise laboratory practice notes associated with Plateletcrit (PCT). Apply pearls alongside institutional protocols.
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