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  • Platelet large cell ratio (P-LCR) as a Diagnostic Biomarker: From Inflammation to Hematological Disorders
  • Alireza Khanahmad,1,*
    1. Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medicine, Kerman University of Medical Sciences, Kerman, Iran


  • Introduction: Platelets (PLTs), also known as thrombocytes, are small discoid-shaped anucleated cells. The primary role of PLTs is to prevent and stop bleeding. Furthermore, tissue remodeling, wound healing, inflammation, and proliferative processes are conducted in the presence of PLTs. Platelet indices may dysregulate in several disorders. Platelet large cell ratio (P-LCR) demonstrates the percentage of large PLTs with a higher volume than 12 fl. The normal range of P-LCR is up to 50%. Younger and more active platelets tend to be larger. The increased levels of P-LCR may indicate higher production of platelets in response to various situations. Therefore, P-LCR can be an important parameter to help the diagnosis of various pathological conditions. This study aims to overview the situations in which P-LCR either elevates or decreases. This paper provides new insights into the importance and diagnostic roles of P-LCR.
  • Methods: A search was conducted in PubMed utilizing the following keywords: “platelet indices” OR “platelet large cell ratio” OR “P-LCR” OR PLCR. All the literature was included without the consideration of time and article type. Non-English publications were excluded. An additional manual search was also conducted in the reference list of the related publications.
  • Results: P-LCR is now used in clinical settings to provide additional information about a patient's health, especially in cases where platelet characteristics may be of interest. It is considered alongside other blood parameters to help diagnosis and risk assessment, particularly in the context of inflammatory and cardiovascular diseases. According to the previous literature, elevated P-LCR may accompany Inflammatory disorders, infectious diseases, bone marrow disorders, recovery from bleeding, and certain drug administration (e.g., corticosteroids). In contrast, aplastic anemia, hematological disorders, and administration of chemotherapeutic agents can decrease the P-LCR level. During an acute phase as well as a major trauma, the patient's need for producing platelets increases. These conditions may result in the release of younger and larger platelets. Thus, P-LCR level elevates. Besides, hematologic disorders such as myeloproliferative disorders may result in the presence of large circulating platelets. Generally, most of the conditions with cytopenia especially thrombocytopenia such as aplastic anemia or myelodysplastic syndromes lead to a lower generation of platelets and subsequent P-LCR drop. Some other therapeutic agents including chemotherapeutic drugs (e.g., methotrexate, 5-fluorouracil, and others), radiotherapy, anti-platelet agents (e.g., aspirin and clopidogrel), thrombopoietin receptor agonists (e.g., romiplostim), and bone marrow suppressive drugs (e.g., azathioprine) affect the P-LCR level.
  • Conclusion: Although the development of new parameters such as P-LCR has provided new insights into the interpretation of the laboratory results, further research is needed to determine the regulators and interfering factors of these indices. It is also suggested that P-LCR should be considered in conjunction with the overall health and the clinical symptoms of the patient along with some other platelet indices, such as platelet count and mean platelet volume (MPV), to provide a more accurate assessment of a patient's platelet function. Overall, an increased P-LCR may indicate a higher demand for PLT production. On the other hand, both elevated destruction and diminished production of PLTs may lower the P-LCR.
  • Keywords: Platelet large cell ratio, Platelet, Hematologic disease, Inflammation, Diagnosis