Platelet function assays

Rand, Margaret L.; Leung, Roland; Packham, Marian A.

doi:10.1016/s1473-0502(03)00050-8

Cited by 178 publications

(146 citation statements)

References 48 publications

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“…However, this test does not distinguish between the varieties of causes of disturbed primary hemostasis. [1][2][3] This can be tested more specifically in vitro, but current methods require relative high numbers of platelets and are consequently unsuitable for patients with low platelet counts. 1,2,4 Immune thrombocytopenia (ITP) is the most common cause of primary thrombocytopenia in children, with an incidence of ;1 in 20 000 children.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] This can be tested more specifically in vitro, but current methods require relative high numbers of platelets and are consequently unsuitable for patients with low platelet counts. 1,2,4 Immune thrombocytopenia (ITP) is the most common cause of primary thrombocytopenia in children, with an incidence of ;1 in 20 000 children. 5,6 Although the pathophysiology of ITP is not fully understood, 2 major forms are recognized: acute ITP and chronic ITP.…”

Section: Introductionmentioning

confidence: 99%

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Functional platelet defects in children with severe chronic ITP as tested with 2 novel assays applicable for low platelet counts

Bladel

Laarhoven

Heijden

et al. 2014

Blood

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Key Points• Pediatric chronic ITP patients with a severe bleeding phenotype exhibit functional platelet defects.• The platelet microaggregation test and the platelet reactivity assay are able to assess platelet function at extremely low platelet count.Immune thrombocytopenia (ITP) is an autoimmune disease with a complex heterogeneous pathogenesis and a bleeding phenotype that is not necessarily correlated to platelet count. In this study, the platelet function was assessed in a well-defined cohort of 33 pediatric chronic ITP patients. Because regular platelet function test cannot be performed in patients with low platelet counts, 2 new assays were developed to determine platelet function: first, the microaggregation test, measuring in platelets isolated from 10 mL of whole blood the platelet potential to form microaggregates in response to an agonist; second, the platelet reactivity assay, measuring platelet reactivity to adenosine diphosphate (ADP), convulxin (CVX), and thrombin receptor activator peptide in only 150 mL of unprocessed whole blood. Patients with a severe bleeding phenotype demonstrated a decreased aggregation potential upon phorbol myristate acetate stimulation, decreased platelet degranulation following ADP stimulation, and a higher concentration of ADP and CVX needed to activate the glycoprotein IIbIIIa complex compared with patients with a mild bleeding phenotype. In conclusion, here we have established 2 functional tests that allow for evaluation of platelet function in patients with extremely low platelet counts ( <10 9 ). These tests show that platelet function is related to bleeding phenotype in chronic ITP. (Blood. 2014;123(10):1556-1563

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Functional platelet defects in children with severe chronic ITP as tested with 2 novel assays applicable for low platelet counts

Bladel

Laarhoven

Heijden

et al. 2014

Blood

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“…Complete blood count, including optical-impedance platelet count and mean platelet volume, and immunoplatelet count (CD 61), was done using the Abbott CellDyn Sapphire instrument (Abbott, Abbott Park, IL). The platelet function analyzer (PFA-100V R , Dade-Behring, Marburg, Germany) was used to measure closure times representing global platelet function (both CT c/epi and CT c/ADP cartridges were applied) [15,16]. RIPA was done with the Chrono-Log whole blood lumi-aggregometer (Chrono-Log, Havertown, PA) using ristocetin at 1.5 mg/mL final concentration [16].…”

mentioning

confidence: 99%

“…The platelet function analyzer (PFA-100V R , Dade-Behring, Marburg, Germany) was used to measure closure times representing global platelet function (both CT c/epi and CT c/ADP cartridges were applied) [15,16]. RIPA was done with the Chrono-Log whole blood lumi-aggregometer (Chrono-Log, Havertown, PA) using ristocetin at 1.5 mg/mL final concentration [16]. The RIPA was quantified and reported as a percentage of maximum transillumination with PPP.…”

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confidence: 99%

Clinical phenotype in heterozygote and biallelic Bernard‐Soulier syndrome—A case control study

et al. 2014

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Bernard-Soulier syndrome (BSS) is a rare severe autosomal recessive bleeding disorder. To date heterozygous carriers of BSS mutations have not been shown to have bleeding symptoms. We assessed bleeding using a semi-quantitative questionnaire, platelet parameters, PFA-100 closure times, ristocetin response, GP Ib/IX expression and VWF antigen in 14 BSS patients, 30 heterozygote carriers for related mutations and 29 controls. Eight mutations in GP1BA, GP1BB or GP9 were identified including four previously unknown pathogenic mutations. Subjects with BSS reported markedly more mucocutaneous bleeding than controls. Increased bleeding was also observed in heterozygotes. Compared to controls, patients with BSS had lower optical platelet counts (P < 0.001), CD61-platelet counts (P < 0.001) and higher mean platelet volume (17.7 vs. 7.8 fL, P < 0.001) and ristocetin response and closure times were unmeasurable. Heterozygotes had higher MPV (9.7 fL, P < 0.001) and lower platelet counts (P < 0.001) than controls but response to ristocetin and closure times were normal. The VWF was elevated in both BSS and in heterozygotes (P 5 0.005). We conclude that heterozygotes for BSS mutations have lower platelet counts than controls and show a bleeding phenotype albeit much milder than in BSS. Both patients with BSS and heterozygote carriers of pathogenic mutations have raised VWF.

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“…Both standard and heparinasemodified tests can be performed to increase the sensitivity of TEG/ROTEM testing, specifically geared to determine the effects of low molecular weight heparin and heparinoids on coagulation [6]. Because platelets play a key role in overall coagulation, the assessment of the platelet function, more than their number, is critical in the perioperative setting [29,30]; Munoa et al [31]. Traditional assays, such as turbidimetric platelet aggregometry, are still considered a clinical standard for platelet function testing.…”

Section: Monitoring Anticoagulationmentioning

confidence: 99%

Perioperative coagulopathy monitoring

et al. 2013

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Coagulopathy is common in orthopedic surgery patients either due to acquired factors, such as surgery, trauma, medications, or hemorrhage. Perioperative monitoring of blood coagulation is critical to diagnose the causes of hemorrhage, guide hemostatic therapies, predict the risk of bleeding during surgical procedures, and reduce risk of postoperative cardiac and thromboembolic events. In contrast to previous interventions that measure specific portions of the clotting cascade (such as intrinsic or extrinsic pathways or platelet aggregation), ''Point-ofcare'' coagulation monitoring devices assess the viscoelastic properties of whole blood. These techniques have the potential to measure the entire clotting process, starting with fibrin formation, clot retraction, and fibrinolysis. Furthermore, the coagulation status of patients is assessed in whole blood, allowing the plasmatic coagulation system to interact with platelets and red cells, and thereby providing useful additional information on platelet function. Improved monitoring of coagulopathy is particularly important as new anticoagulant drugs emerge that affect the clotting cascade in novel ways, including the inhibition of intrinsic and extrinsic pathways and platelet function. It is important for orthopedic surgeons to understand the pharmacology and reversal of these drugs in the perioperative setting. The purpose of this review is to review the current techniques to monitoring perioperative coagulopathy and to identify the manner in which novel anticoagulant medications affect the clotting cascade with particular interest in trauma and spine surgery.

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Platelet function assays

Cited by 178 publications

References 48 publications

Functional platelet defects in children with severe chronic ITP as tested with 2 novel assays applicable for low platelet counts

Functional platelet defects in children with severe chronic ITP as tested with 2 novel assays applicable for low platelet counts

Clinical phenotype in heterozygote and biallelic Bernard‐Soulier syndrome—A case control study

Perioperative coagulopathy monitoring

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