Previous studies have reported inconsistent associations between platelet count (PLT) and cancer survival. However, whether there is linear causal effect merits in-depth investigations. We conducted a cohort study using the UK Biobank and a two-sample Mendelian randomization (MR) analysis. PLT levels were measured prior to cancer diagnosis. We adopted overall survival (OS) as the primary outcome. Cox models were utilized to estimate the effects of PLTs on survival outcomes at multiple lag times for cancer diagnosis. We employed 34 genetic variants as PLT proxies for MR analysis. Linear and non-linear effects were modeled. Prognostic effects of gene expression harboring the instrumental variants were also investigated. A total of 65 471 cancer patients were included. We identified a significant association between elevated PLTs (per 100 × 10/L) and inferior OS (HR: 1.07; 95% CI: 1.04-1.10;  < .001). Similar significant associations were observed for several cancer types. We further observed a U-shaped relationship between PLTs and cancer survival ( < .001). Our MR analysis found null evidence to support a causal association between PLTs and overall cancer survival (HR: 1.000; 95% CI: 0.998-1.001;  = .678), although non-linear MR analysis unveiled a potential greater detrimental effect at lower PLT range. Expression of eleven PLT-related genes were associated with cancer survival. Early detection of escalated PLTs indicated possible occult cancer development and inferior subsequent survival outcomes. The observed associations could potentially be non-linear. However, PLT is less likely to be a promising therapeutic target.

Hemolysis is associated with thrombosis and vascular dysfunction, which are the pathological components of many diseases. Hemolytic products, including hemoglobin and hemin, activate platelets (PLT). Despite its activation, the effect of hemolysis on platelet clearance remains unclear, It is critical to maintain a normal platelet count and ensure that circulating platelets are functionally viable. In this study, we used hemin, a degradation product of hemoglobin, as a potent agonist to treat platelets and simulate changes in vivo in mice. Hemin treatment induced activation and morphological changes in platelets, including an increase in intracellular Ca levels, phosphatidylserine (PS) exposure, and cytoskeletal rearrangement. Fewer hemin-treated platelets were cleared by macrophages in the liver after transfusion than untreated platelets. Hemin bound to glycoprotein Ibα (GPIbα), the surface receptor in hemin-induced platelet activation and aggregation. Furthermore, hemin decreased GPIbα desialylation, as evidenced by reduced Ricinus communis agglutinin I (RCA- I) binding, which likely extended the lifetime of such platelets in vivo. These data provided new insight into the mechanisms of GPIbα-mediated platelet activation and clearance in hemolytic disease.

Currently, the standard treatment for patients who have undergone percutaneous coronary intervention (PCI) following acute myocardial infarction (MI) involves dual antiplatelet therapy (DAPT) with a combination of aspirin and a potent P2Y12 receptor inhibitor. However, the potential benefits of aspirin were partially constrained by the intolerance of some patients. The safety and efficacy of indobufen, an alternative antiplatelet agents to aspirin, in patients with AMI after PCI are yet to be thoroughly investigated.This retrospective study was conducted at a single center and utilized propensity score matching. The enrollment spanned from January 2019 to June 2022, incorporating patients with AMI after PCI. The participants were categorized into two groups based on discharged prescriptions: the aspirin DAPT group and the indobufen DAPT group. The primary endpoint focused on net adverse clinical event (NACE), defined as a composite outcome, including cardiac death, recurrence of MI, definite or probable stent thrombosis (ST), target lesion revascularization (TLR), ischemic stroke and Bleeding Academic Research Consortium (BARC) criteria type 2, 3, or 5. All the patients underwent a one-year follow-up period.A total of 1451 patients were enrolled in this study, with 258 assigned to the indobufen DAPT group and 1193 to the aspirin DAPT group. Following 1:1 propensity score matching, 224 patients were retained in each group. In the indobufen DAPT group, 58 individuals (25.9%) experienced the primary endpoint within one year, compared to 52 individuals (23.2%) in the aspirin DAPT group (HR 1.128, 95% CI 0.776-1.639,  = .527). Specifically, no significant differences were observed in either the efficacy endpoint (MACCE, 20.1% vs. 14.7%, HR 1.392, 95% CI 0.893-2.170,  = .146) or the safety endpoint (BARC 2,3 or 5, 8.04% vs. 10.30%, HR 0.779,  = .427). These findings remained consistent at 1, 3, or 6 months. Additionally, the incidence of gastrointestinal symptoms were significantly lower in indobufen DAPT group compared to the aspirin DAPT group (7.1% vs. 14.3%,  = .022).Our research reveals that the efficacy and safety of indobufen are comparable to aspirin in Chinese patients with AMI following PCI. Given the potential advantages of indobufen in alleviating gastrointestinal symptoms, we propose it as a viable alternative for individuals intolerant to aspirin.

Clinical research data showed a series of adverse events in the delivery period of primary immune thrombocytopenia (ITP) patients, including high cesarean section rate. Consensus report proposed that for patients with platelet count below 50 × 10/L, prednisone or intravenous immunoglobulins (IVIg) can be given to raise the platelet count in third trimester in preparation for labor.

Thromboembolic events are common in patients with essential thrombocythemia (ET). However, the pathophysiological mechanisms underlying the increased thrombotic risk remain to be determined. Here, we perform the first phenotypical characterization of platelet expression using single-cell mass cytometry in six ET patients and six age- and sex-matched healthy individuals. A large panel of 18 transmembrane regulators of platelet function and activation were analyzed, at baseline and after stimulation with thrombin receptor-activating peptide (TRAP). We detected a significant overexpression of the activation marker CD62P (p-Selectin) ( = .049) and the collagen receptor GPVI ( = .044) in non-stimulated ET platelets. In contrast, ET platelets had a lower expression of the integrin subunits of the fibrinogen receptor GPIIb/IIIa CD41 ( = .036) and CD61 ( = .044) and of the von Willebrand factor receptor CD42b ( = .044). Using the FlowSOM algorithm, we identified 2 subclusters of ET platelets with a prothrombotic expression profile, one of them (cluster 3) significantly overrepresented in ET (22.13% of the total platelets in ET, 2.94% in controls,  = .035). Platelet counts were significantly increased in ET compared to controls ( = .0123). In ET, MPV inversely correlated with platelet count (=-0.96). These data highlight the prothrombotic phenotype of ET and postulate GPVI as a potential target to prevent thrombosis in these patients.

Platelet type bleeding disorder-18 (BDPLT18) caused by mutations of Ras guanyl releasing protein 2 () is a relatively rare, new autosomal recessive disorder. Here, we reported a splice mutation in gene in the patient with recurrent epistaxis and nasal vascular malformation. The patient, an 8-year-old girl, suffered from anemia due to frequently severe recurrent epistaxis, requiring regular blood transfusions every 2-3 months. Hematological investigations showed moderate anemia (Hb: 89 g/L), normal platelet count, morphology, and platelet glycoproteins. Arachidonic acid and adenosine diphosphate induced platelet aggregation was markedly reduced in the patient. A homozygous splice variant (C.74-1 G>C) in gene, located within the exon 3, was detected by next-generation sequencing. Interestingly, we identified nasal vascular malformation by percutaneous super-selective angiography during the treatment of an intractable epistaxis. Our case further support that genetic testing should be performed for some unexplained bleeding diseases.

This trial targeted to analyze the effects of different doses of tirofiban combined with dual antiplatelet drugs on platelet indices, vascular endothelial function, and major adverse cardiovascular events (MACE) in patients with acute ST-segment elevated myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI). A total of 180 patients with STEMI who underwent PCI were divided into Group A, Group B, and Group C (60 cases per group). Group A was given conventional medication, and Groups B and C were given a standard dose (10 μg/kg) and a high dose (20 μg/kg) of tirofiban on the basis of Group A, respectively. Thrombolysis in myocardial infarction (TIMI) myocardial perfusion grade and TIMI blood flow grade were compared. Myocardial enzymes, platelet indices, vascular endothelial function, inflammatory factors, and cardiac function indices were detected. In-hospital bleeding events and follow-up MACE were recorded. After PCI, Group C had a higher number of TIMI myocardial perfusion grade III and TIMI blood flow grade III versus Group A. Group C achieved the greatest changes in myocardial enzymes, platelet indices, vascular endothelial function-related factors, inflammatory factors, and cardiac function indices, followed by Group B and Group A. The incidence of bleeding events was higher in Group C than in Group A, and that of MACE in Group C was lower than in Group A. The addition of high-dose tirofiban to PCI and dual antiplatelet drugs for STEMI patients can improve myocardial blood perfusion, cardiac function, and vascular endothelial function, inhibit platelet activation and aggregation, and reduce the occurrence of MACE.

Receptor-induced tyrosine phosphorylation of spleen tyrosine kinase (Syk) has been studied extensively in hematopoietic cells. Metabolic mapping and high-resolution mass spectrometry, however, indicate that one of the most frequently detected phosphorylation sites encompassed S297 (S291 in mice) located within the linker B region of Syk. It has been reported that Protein kinase C (PKC) phosphorylates Syk S297, thus influencing Syk activity. However, conflicting studies suggest that this phosphorylation enhances as well as reduces Syk activity. To clarify the function of this site, we generated Syk S291A knock-in mice. We used platelets as a model system as they possess Glycoprotein VI (GPVI), a receptor containing an immunoreceptor tyrosine-based activation motif (ITAM) which transduces signals through Syk. Our analysis of the homozygous mice indicated that the knock-in platelets express only one isoform of Syk, while the wild-type expresses two isoforms at 69 and 66 kDa. When the GPVI receptor was activated with collagen-related peptide (CRP), we observed an increase in functional responses and phosphorylations in Syk S291A platelets. This potentiation did not occur with AYPGKF or 2-MeSADP, although they also activate PKC isoforms. Although there was potentiation of platelet functional responses, there was no difference in tail bleeding times. However, the time to occlusion in the FeCl injury model was enhanced. These data indicate that the effects of Syk S291 phosphorylation represent a significant outcome on platelet activation and signaling but also reveals its multifaceted nature demonstrated by the differential effects on physiological responses .

Viral infections can lead to platelet activation and hemostatic complications. However, the extent to which platelet reactivity remains altered after convalescence, contributing to long-term health impairments as observed after COVID-19 is not yet fully understood. Therefore, we conducted a cohort study (DRKS00025217) to determine platelet function in individuals convalesced from mild COVID-19. Assays were performed with blood from convalescents at 2-15 weeks and 6-10 months after convalescence, focusing on platelet aggregation, activation markers, and thrombin formation. In addition, two other potentially relevant factors for platelet function were examined: the immunomodulatory mediator sphingosine-1-phosphate (S1P) and the platelet expression of the transporter MRP4 (ABCC4). Our findings indicate that robust platelet functions, including platelet aggregation determined by light transmission aggregometry, and thrombin formation, were not altered in convalescents compared to matched control individuals. However, an elevation in subtle platelet activation markers, such as P-selectin surface expression and activation of glycoprotein IIb/IIIa, was observed 2-15 weeks after convalescence. This was accompanied by an increased expression of MRP4 in platelets and significantly elevated levels of S1P in platelet-poor plasma. Our findings suggest increased platelet sensitization and a pro-inflammatory state even after convalescence from mild COVID-19, pointing toward MRP4 and S1P as associated factors.

Cartilage injury is common in orthopedics and cartilage tissue engineering provides a therapeutic direction for cartilage regeneration. Albumin (ALB)-platelet-rich fibrin (PRF) is speculated to be an ideal natural scaffold material for cartilage tissue engineering theoretically as a product derived from human venous blood. Through and experiments, it was demonstrated that ALB-PRF displayed porous structure and slowly released growth factors (TGF-β1, PDGF-AA, PDGF-AB, PDGF-BB, EGF, IGF-1 and VEGF), ALB-PRF conditioned media promoted proliferation, migration, adhesion, phenotype maintenance and extracellular matrix secretion of rabbit chondrocytes. Moreover, ALB-PRF facilitated chondrogenesis , the regenerative cartilage formed by ALB-PRF/chondrocytes was histologically similar to that of natural knee joint cartilage, the regenerative cartilage expressed cartilage differentiation marker (SOX9, ACAN and COL II), and proliferation marker PCNA and secreted abundant glycosaminoglycans (GAGs) in extracellular matrix. In conclusion, ALB-PRF promoted the migration, proliferation and phenotype maintenance of chondrocytes . Its loose, porous structure and rich growth factors contained enhanced cell adhesion and growing into the materials. ALB-PRF facilitated chondrogenesis of chondrocytes

Soluble CLEC-2 is anticipated to have various clinical applications as a novel biomarker for in vivo platelet activation, assessable using plasma obtained through routine sampling procedures. While sCLEC-2 has been measured using ELISA, we have developed a highly sensitive chemiluminescence enzyme immunoassay (CLEIA) reagent that can yield results in approximately 19 minutes. This study aims to assess its fundamental performance and explore the molecular forms of sCLEC-2 measured in patient samples. We examined the sensitivity, precision, linearity, influence of endogenous substances, residual platelets, as well as the correlation with the ELISA method, for the sCLEC-2 CLEIA reagent. The CLEIA method demonstrated sufficient sensitivity for levels observed in healthy donors, and its basic performance was satisfactory. It exhibited a strong correlation with the previously described ELISA method, with reference ranges that did not significantly differ from the ELISA data. The sCLEC-2 reference range for males was significantly higher than that for females. Since it is known that sCLEC-2 exists in shed form and microparticle form, we investigated molecular forms of sCLEC-2 measured by the CLEIA in in vitro-activated platelets and in patients' plasma using gel filtration. It is considered that the CLEIA method shows significantly stronger reactivity with the shed form compared to the microparticle form. Studies using gel filtration of patient samples also suggest that the shed form is being primarily measured. The sCLEC-2 CLEIA reagent exhibits robust performance and is promising for clinical applications.

Severe thermal injury significantly impacts upon hemostasis and is associated with classical changes to the circulating platelet count with a nadir followed by a rebound thrombocytosis at days ~3 and ~15 post-injury, respectively. To date, few studies have assessed platelet function following thermal injury as platelet tests often require large quantities of blood, are not representative of normal platelet pathophysiology, and are usually dependent on a normal platelet count. The purpose of this study was to measure platelet thrombus formation using a whole blood flow chip-based system following thermal injury and to study how platelet counts may impact upon the measurement. Adult (≥16 years) patients ( = 10) with ≥ 20% total burn surface area (TBSA) burn were recruited within 24 h of injury. Healthy controls ( = 25) were also recruited. Whole blood counts were measured using a hematology analyzer (Sysmex XN-1000). Platelet function was measured using the Total Thrombus-formation Analyzer System (T-TAS) within chips coated with tissue factor and collagen at shear rates of either 600 sec (AR chips) or 1200 sec (HD chips), the latter test being independent of platelet count. We confirmed the classical nadir in platelet counts following severe thermal injury at days 2, 3, 4 ( < 0.0001) and day 5 ( < 0.01) post-injury compared to healthy controls. Physiological platelet thrombus formation was significantly ( < 0.01) abnormal at day 3 post-injury using the AR chips but was related to the platelet count. However, although platelet dysfunction was not significant using HD chips, some of the results were independent of platelet count. A small number of samples, however, still gave abnormal results suggesting that there can be an underlying acquired platelet functional abnormality. Furthermore, the AR chip Area Under the Curve (AUC) was significantly lower on day 1 post-injury and negatively associated with severity of injury (TBSA,  < 0.05) and higher platelet function (AUC) positively associated with survival ( < 0.05). This study suggests that measuring platelet dysfunction within a more physiological test may have potential clinical utility. Larger studies are required to fully understand the impact of platelet dysfunction following severe thermal injury.

The functional role of platelets is intricately linked to the dynamic organization of two main components of the cytoskeleton, microtubules and actin fibers. Throughout the phases of platelet activation, spreading, and retraction, both of these essential polymers undergo continuous and orchestrated reorganization. Our investigation of the dynamic cytoskeletal changes during these phases highlights a sequential remodeling of the actin cytoskeleton in adherent platelets from the formation of initial actin nodules through the development of stress fibers and a subsequent return to nodular structures. Concurrently, the marginal ring of microtubules, characteristic of resting platelets, undergoes a re-organization induced by marginal band extension and coiling toward the formation of star-like bundles of microtubules. Subsequently, these bundles are dispersed into individual microtubules, which are re-bundled at later stages before ring-like structures are formed again. These findings suggest a compelling tendency for both cytoskeletal components to revert to their original configurations. Notably, the early steps of platelet cytoskeleton reorganizations have previously been shown to be regulated by the signaling cascade triggered during platelet activation, which leads to an increase of cytosolic calcium concentrations. We show here that later steps are potentially regulated by a progressive decrease of intracellular calcium concentrations as platelets approach the end of their functional lifespan.

Dense-granule deficiency (DGD) is an inherited platelet disorder due to the absence of dense granules essential for activation of platelets in the event of vascular injury. Decreased platelet dense granules can be detected by electron microscopy, while other tests of hemostasis, including platelet function analyzer (PFA®) closure times, may be normal. The present case report describes a patient with a lifelong history of mucocutaneous bleeding and excessive hemorrhage with resection of vestibular Schwannoma. After hemostasis was obtained the case was aborted and the neurosurgeon noted bleeding resembled as if patient was on an antiplatelet drug. Subsequent hematologic workup revealed a severe platelet function disorder. There is a paucity of literature on management of intracranial neurosurgery in patients with inherited platelet disorders. Patients undergoing major surgical procedures often receive tranexamic acid (TXA), desmopressin, and/or human-leukocyte antigen (HLA)-matched platelet transfusions. We review the clinical management of intracranial tumor surgery, as well as Cyberknife radiosurgery, in our patient with DGD. After diagnosis was known, thoughtful hemostatic planning with empiric platelet transfusions and TXA prevented recurrent bleeding.

Platelet-derived extracellular vesicles (PEVs) are released by platelets in the blood circulation, which carry a rich bio-molecular cargo influential in intercellular communications. PEVs can enter the lymph, bone marrow, and synovial fluid as nano-sized particles, while platelets cannot cross tissue barriers. Considering the advantages of PEVs such as low immunogenicity, high regulation of signal transduction, and easy obtainment, PEVs may be promising therapeutic tools for medical applications. The exceptional functional roles played by PEVs explain the recent interest in exploring new cell-free therapies that could address needs in angiogenesis, regenerative medicine, and targeted drug delivery. The review takes a critical look at the main advances of PEVs in the treatment of diseases by presenting the latest knowledge from the performed studies, in order to enhance the further translation of the PEVs research into feasible therapeutic applications.

Liver failure and cirrhosis are characterized by abnormal hemostasis with aberrant platelet activation. In particular, the consequences of cholestatic liver disease and molecular mechanisms, including the role of bile acids leading to impaired platelet responses, are not well understood. Here, we demonstrate that bile acids inhibit human and murine platelet activation, adhesion and spreading, leading to reduced thrombus formation under flow conditions. We identified the G-protein coupled receptor TGR5 in platelets and provide support for its role as mediator of bile acid-induced impairment of platelet activation. In the liver, TGR5 couples to Gαs proteins, activates the adenylate cyclase to induce a transient cAMP rise and stimulates the MAPK signaling pathway to regulate cholangiocyte proliferation, hepatocyte survival and inflammation. In this report, we demonstrate that the genetic deficiency of TGR5 in mice led to enhanced platelet activation and thrombus formation, suggesting that TGR5 plays an important role in hemostasis. Mechanistically, platelet inhibition is achieved by TGR5 mediated PKA activation and modulation of AKT and ERK1/2 phosphorylation. Thus, this report provides evidence for the ability of TGR5 ligands to reduce platelet activation and identifies TGR5 agonism as a new target for the prevention of cardiovascular diseases.

Inherited thrombocytopenias (ITs) encompass a group of rare disorders characterized by diminished platelet count. Recent advancements have unveiled various forms of IT, with inherited thrombocytopenia 2 (THC2) emerging as a prevalent subtype associated with germline variants in the critical 5' untranslated region of the gene. This region is crucial in regulating the gene expression of , particularly in megakaryocytes. THC2 is an autosomal dominant disorder presenting as mild-to-moderate thrombocytopenia with minimal symptoms, with an increased risk of myeloproliferative malignancies. In our study of a family with suspected IT, three affected individuals harbored the c.-118C>T variant, while four healthy members carried the c.-140C>G variant. We performed a functional analysis by studying platelet-specific gene expression levels using quantitative real-time polymerase-chain reaction. Functional analysis of the c.-118C>T variant showed a significant increase in expression in affected individuals, supporting its pathogenicity. On the contrary, carriers of the c.-140C>G variant exhibited normal platelet counts and no significant elevation in the expression, indicating the likely benign nature of this variant. Our findings provide evidence confirming the pathogenicity of the c.-118C>T variant in THC2 and suggest the likely benign nature of the c.-140C>G variant.

Septic shock is a life-threatening disease worldwide often associated with thrombocytopenia. Platelets play a crucial role in bridging the gap between immunity, coagulation, and endothelial cell activation, potentially influencing the course of the disease. However, there are few studies specifically evaluating the impact of thrombocytopenia on the prognosis of pediatric patients. Therefore, the study investigates effects of early thrombocytopenia in the prognosis of children with septic shock. Pediatric patients with septic shock from 2015 to 2022 were included monocentrically. Thrombocytopenia was defined as a platelet count of <100 × 10/L during the first 24 hours of septic shock onset. The primary outcome was the 28-day mortality. Propensity score matching was used to pair patients with different platelet counts on admission but comparable disease severity. A total of 419 pediatric patients were included in the analysis. Patients with thrombocytopenia had higher 28-day mortality (55.5% vs. 38.7%,  = .005) compared to patients with no thrombocytopenia. Thrombocytopenia was associated with reduced 28-PICU free days (median value, 0 vs. 13 days,  = .003) and 28-ventilator-free (median value, 0 vs. 19 days,  = .001) days. Among thrombocytopenia patients, those with platelet count ≤50 × 10/L had a higher 28-day mortality rate (63.6% vs. 45%,  = .02). Multiple logistic regression showed that elevated lactate (adjusted odds ratio (OR) = 1.11; 95% confidence interval (CI): 1.04-1.17; <0.001) and white blood cell (WBC) count (OR = 0.97; 95% CI: 0.95-0.99;  = .003) were independent risk factors for the development of thrombocytopenia. Thrombocytopenia group had increased bleeding events, blood product transfusions, and development of organ failure. In Kaplan-Meier survival estimates, survival probabilities at 28 days were greater in patients without thrombocytopenia ( value from the log-rank test,  = .004). There were no significant differences in the type of pathogenic microorganisms and the site of infection between patients with and without thrombocytopenia. In conclusion, thrombocytopenia within 24 hours of shock onset is associated with an increased risk of 28-day mortality in pediatric patients with septic shock.

The impact of the biophysical environment on the platelet storage lesion (PSL) has mainly focused on reduced temperature storage, overlooking the significance of storage-induced shear stress. Shear stress in platelet storage refers to the frictional force acting parallel to the bag surface and exists solely through the implementation of agitation. This study investigates whether minimizing exposure to agitation-induced shear stress can alleviate the unexplained loss of function in stored platelet concentrates for neonatal transfusion (neonatal PCs). Using particle tracking analysis, fluid motion was measured in neonatal and adult platelet storage bags under agitation frequencies ranging from 20-60 rpm. Platelets stored at 20-60 rpm agitation over 8 days were examined by biochemical analysis, aggregation, and expression of activation markers. Results indicate that neonatal PCs experience significantly higher storage-induced shear stress compared to adult doses, leading to reduced functionality and increased activation from day 2 of storage. Adjusting the neonatal PC agitation frequency to 20 rpm improved functionality in early storage, while 40 rpm maintains this improvement throughout storage with reduced activation, compared to 60 rpm storage. This study confirms that small volume PC storage for neonatal use contributes to the PSL through the induction of shear stress, suggesting further evaluation of the recommended agitation frequency for neonatal PCs or postponement of the production of neonatal PCs until requested for neonatal transfusion.

Acquired disorders of platelet function are an underdiagnosed cause of bleeding tendency. A 14-year-old girl developed moderate mucocutaneous bleeding two weeks after a infection successfully treated with clarithromycin. The patient was referred to us 7 months later for laboratory investigation of the persisting bleeding diathesis. The patient's personal and family histories were negative for bleeding disorders. Complete blood count, von Willebrand Factor levels and coagulation tests were normal; platelet aggregation, ATP secretion, δ-granules content and serum thromboxane B2 levels were defective. At follow-up visits, laboratory parameters and the bleeding diathesis progressively normalized within 2 years. The patient's condition is compatible with a diagnosis of acquired Storage Pool Deficiency (SPD), associated with defective thromboxane A2 production. To our knowledge, this is the first case of acquired, transient SPD with spontaneous remission. The pathogenic role of infection or clarithromycin is possible, albeit uncertain.

Light transmission aggregometry (LTA) is a method used to investigate platelet functions in platelet-rich plasma (PRP), notably when screening for platelet disorders. Various national guidelines and recommendations help in setting up the LTA test in specialized laboratories. However, due to the nature of the sample matrix and its subsequent specificities, more accurate positions are needed to achieve LTA accreditation according to the standard NF EN ISO 15 189. We reviewed guidelines and recommendations as they can be useful in the accreditation process, and we conducted a survey on LTA practice among members of the ) in 2021. We formulated 28 proposals, which have been approved by vote within the SFTH. All aspects to take into consideration for the proper conduct of LTA assays and their accreditation have been covered. Notably, preanalytical, analytical and postanalytical aspects are depicted, including blood sampling, PRP preparation, instruments, agonists, performance assessment, personnel training and data interpretation. This document, essentially representing a French position paper on the current recommendations and subsequent proposals for LTA accreditation, might prove useful also outside France for relevant laboratories and auditors involved in LTA accreditation.