Platelet parameters for distinguishing between inherited macrothrombocytopenia and acquired thrombocytopenia: a retrospective case–control study

Inherited macrothrombocytopenia (IMT) is characterized by increased platelet volume. Using platelet parameters, including platelet count, mean platelet volume (MPV), platelet-large cell ratio (P-LCR), and platelet distribution width, to differentiate IMT from acquired thrombocytopenia (AT) in the Chinese population is unclear. This study aimed to evaluate these parameters and determine optimal thresholds for early IMT identification. This single-center, retrospective case–control study included IMT patients from 1 January 2022 to 31 January 2024. Age- and sex-matched AT patients and healthy individuals were selected (1:3 ratio). Platelet parameters were compared using a one-way analysis of variance and the Kruskal–Wallis test. The ability of platelet parameters to identify IMT was assessed using the receiver operating characteristic curve, with the optimal threshold determined using the Youden index. This study included 13 IMT patients, 39 AT patients, and 39 controls. The MPV and P-LCR were significantly higher in IMT than in AT patients (<i>P</i> &lt; 0.05) and strongly differentiated between groups. The area under the curve (95% confidence interval) for MPV and P-LCR were 0.865 (0.724–1.000) and 0.860 (0.719–1.000), respectively. The optimal MPV and P-LCR thresholds for IMT were 14.55 fL and 58%, respectively. The MPV was most important for distinguishing IMT from patients with thrombocytopenia. What is the background? Inherited macrothrombocytopenia (IMT), a rare and heterogeneous genetic disorder, is the most common subtype of inherited thrombocytopenia (IT), characterized by large platelets, thrombocytopenia, and bleeding tendencies.Due to low awareness, IMT is often misdiagnosed as acquired thrombocytopenia (AT), leading to inappropriate immunosuppression therapy and even splenectomy.Advancements in technology have improved IMT identification but remain time- consuming, costly, and limited to specialized laboratories in developed areas.Platelet size parameters in CBC can raise suspicion of IMT despite limitations in extreme platelet sizes, but thresholds may not apply to the Chinese population due to regional, ethnic, or instrument differences. Inherited macrothrombocytopenia (IMT), a rare and heterogeneous genetic disorder, is the most common subtype of inherited thrombocytopenia (IT), characterized by large platelets, thrombocytopenia, and bleeding tendencies. Due to low awareness, IMT is often misdiagnosed as acquired thrombocytopenia (AT), leading to inappropriate immunosuppression therapy and even splenectomy. Advancements in technology have improved IMT identification but remain time- consuming, costly, and limited to specialized laboratories in developed areas. Platelet size parameters in CBC can raise suspicion of IMT despite limitations in extreme platelet sizes, but thresholds may not apply to the Chinese population due to regional, ethnic, or instrument differences. What are our work and findings? This retrospective case–control study explores platelet parameters in differentiating IMT from AT with thrombocytopenia as the initial clinical manifestation.Mean platelet volume (MPV) and platelet-large cell ratio (P-LCR) were significantly elevated in IMT patients, particularly those with giant platelets (e.g. MYH9-RD, BSS, and STSL), compared to AT and healthy individuals.Platelet size parameters, especially MPV and P-LCR, are crucial for distinguishing IMT from AT and facilitating early diagnosis. This retrospective case–control study explores platelet parameters in differentiating IMT from AT with thrombocytopenia as the initial clinical manifestation. Mean platelet volume (MPV) and platelet-large cell ratio (P-LCR) were significantly elevated in IMT patients, particularly those with giant platelets (e.g. MYH9-RD, BSS, and STSL), compared to AT and healthy individuals. Platelet size parameters, especially MPV and P-LCR, are crucial for distinguishing IMT from AT and facilitating early diagnosis. What is the impact? Raises early suspicion of IMT using platelet parameters in CBC, even without access to advanced technology.Reduces misdiagnosis and inappropriate treatment of IMT as AT, improving patient outcomes and care. Raises early suspicion of IMT using platelet parameters in CBC, even without access to advanced technology. Reduces misdiagnosis and inappropriate treatment of IMT as AT, improving patient outcomes and care.