Platelet Count

Introduction: Pulmonary arterial hypertension (PAH) is frequently associated with thrombotic events, particularly involving the pulmonary microcirculation at sites of vascular injury. We therefore decided to analyse protease-activated receptor 1 (PAR1), a key element in the activation of human platelets by thrombin, in PAH patients in stable clinical condition. Methods: Using flow cytometry, we analyzed platelet PAR1 density, PAR1-mediated exposure of P-selectin and the formation of platelet-leukocyte aggregates in 30 PAH patients aged 11 to 78 years (median 50.5 years). The control group consisted of 25 healthy subjects with the same age range as patients. Results: In patients, total platelet PAR1 density and uncleaved PAR1 density correlated negatively with platelet count (r 2 = 0.33 and r 2 = 0.34 respectively, p b 0.0015). In patients with a low platelet count (b 150 × 10 9 platelets/L), both densities were increased relative to controls (82% and 33% respectively, p b 0.05). Thrombin peptide-induced platelet exposure of P-selectin was directly related to total and uncleaved PAR1 density (respectively, r 2 = 0.33 and r 2 = 0.29, p b 0.0025) and increased in subjects with low platelet count (46% versus those with normal platelet count, p b 0.05). Patients with low platelet count had decreased in vitro thrombin-induced formation of platelet-leukocyte aggregates (57% decrease versus controls, p b 0.05). Conclusions: There seems to be a subpopulation of PAH patients with increased propensity to thrombotic events as suggested by increased platelet PAR1 expression and PAR-mediated surface exposure of P-selectin associated with decreased platelet count.

To establish the anti-platelet or aspirin like effects of flavonoid rich food (chocolate). Methods: This was a non-randomized quasi experimental study in which, 65 healthy adult volunteers, 27 males and 38 females, participated. The subjects included were healthy, non-smoking adults. Health of subjects was evaluated by a questionnaire for which a written informed consent was taken prior to admission in the study. Research protocol was approved by the college's, "Research and Ethical committee". Division of subjects into two groups, a control group which consumed 100mgs of oral aspirin and an interventional group consuming 100mgs oral aspirin and 18.75gms of dark chocolate (flavonoid rich), was carried out. The Bleeding time estimation for both the groups was done by "Duke Method" of bleeding time estimation. Results: Data was analyzed by SPSS 15.0. First, a bivariate analysis was done by comparing both the pre-test groups i.e. before consumption of aspirin and also before consumption of chocolate and aspirin together through independent t-test Later, regression analysis was also done. Bivariate analysis compared both the control and interventional groups. After comparing pre-test groups a p-value of 0.798 was obtained and after comparing post test groups a p-value of 0.006 was determined. Regression analysis yeilded an R-square of 0.25. Conclusion: Chocolate has a significant role in augmenting the anti-platelet effects of aspirin.

Thrombocytopoiesis of 21 multiple myeloma patients undergoing single or double transplant regimen was characterized by measuring the level of reticulated platelets and plasma glycocalicin. Since reticulated platelets are an index of thrombopoietic activity and glycocalicin plasma values are related to platelet damage and turnover, it may be possible to perform a novel type of analysis of the thrombopoietic compartment during the mobilizing regimen and during transplantrelated chemotherapy. Patients underwent mobilizing therapy and first transplant. Some randomized patients also underwent a second transplant with mobilized peripheral blood stem cells. The results show that the percentage of reticulated platelets decreased after therapy and then gradually increased in the recovery phase either during first or second transplant. By contrast, the percentage of reticulated platelets increased until day +8 and then gradually decreased during the mobilizing regimen. The glycocalicin index (glycocalicin plasma value normalized for the individual platelet count) increased significantly both during the course of mobilization and after transplant-related chemotherapy when the platelet number was at its nadir. However, the glycocalicin index was more elevated after transplantrelated chemotherapy than after the mobilizing regimen. Our findings suggest that chemotherapy-related thrombocytopenia may be due to a dual mechanism: thrombocytopenia results from decreased platelet production in addition to increased platelet damage and possible destruction.

Kadidal VV, Mayo DJ, Horne MK (National Institutes of Health, Bethesda, MD 20892, USA) Heparin-induced thrombocytopenia (HIT) due to heparin flushes: a report of three cases (Case Report). J Intern Med 1999; 246: 325±329. Three cases of heparin-induced thrombocytopenia (HIT) are reported that were provoked by daily heparin flushes of central venous access devices.

The present study aimed to determine the effect of oral β-glucan on mucositis and leukopenia in 62 consecutive patients with colorectal cancer treated with an adjuvant FOLFOX-4 regimen. The patients were retrospectively evaluated in 2 groups: one group received β-glucan and the other did not (control group). Leucocytes, neutrophils, and platelets were evaluated before and 1 week after chemotherapy and oral mucositis and diarrhea were noted. Leucocyte and neutrophil counts after chemotherapy in the β-glucan group were 7,300/mm3 and 3,800/mm3, respectively, and the reductions, as compared to baseline, were not significant (p=0.673 and 0.784). The median platelet count was 264,000/mm3 after chemotherapy in the β-glucan group and the reduction, as compared to baseline, was borderline significant (p=0.048). In the control group, reduction in leucocyte, neutrophil, and platelet counts was statistically significant. Oral mucositis and diarrhea were less common in the β-glucan group. We con...

1. Blood coagulation factor levels and the normal ranges of commonly used coagulation tests were established for Sigmodon hispidus. 2. The white cell, red cell and platelet counts have been determined together with the red cell parameters as measured by the Coulter model S-plus. 3. The relationship between the results reported here and those published for related species are discussed.

Introduction: Severe malaria has been attributed partly to the sequestration of Plasmodium falciparum-infected erythrocytes (IEs) in the microvasculature of vital host organs. Identification of P. falciparum cytoadherence phenotypes that are associated with severe malaria may lead to the development of novel strategies against life-threatening malaria.

Platelet transfusions are indicated in a wide variety of clinical conditions especially those with thrombocytopenia. However, without proper clinical practice guidelines, inappropriate transfusions are bound to happen. To ascertain the provision of a quality and appropriate practice of platelet transfusions, an audit study was carried out over a period of one month at the Paediatric Institute, Kuala Lumpur Hospital. A prospective audit was performed during that period whilst a retrospective collection of data was carried out for the previous month for comparison. Based on a set of criteria agreed upon by the audit committee, it was found that in 18.5% (22 of 119) of the cases, the indications for platelet transfusions were inappropriate. The audit committee concluded that there is a need for a more detailed clinical practice guideline for local use to reduce or lower the incidence of inappropriate transfusions of platelets.

Platelet aggregation may be an important factor in the feasibility of transcatheter laser angioplasty. The in vitro effects of increasing doses of CO, laser irradiation on platelet number, function, and surface ultrastructure were examined. Results indicated a progressive doseresponse reduction of both platelet number and function following laser irradiation. By scanning electron microscopy the irradiated platelets showed dose-related changes in pseudopods as well as progressive damage of the cell membrane.

The relationship between the percent phagocytosis of platelets by differentiated THP-1 cells was examined using flowcytometry and the peripheral platelet counts as well as platelet-associated IgG (PAIgG) in 36 patients with secondary dengue virus (DV) infections. The percent phagocytosis and the levels of PAIgG were significantly increased in these patients during the acute phase compared with the healthy volunteers. The increased percent phagocytosis and PAIgG found during the acute phase significantly decreased during the convalescent phase. An inverse correlation between platelet count and the percent phagocytosis (P = 0.011) and the levels of PAIgG (P = 0.041) was found among these patients during the acute phase. No correlation was found, however, between the percent phagocytosis and the levels of PAIgG. Our present data suggest that accelerated platelet phagocytosis occurs during the acute phase of secondary DV infections, and it is one of the mechanisms of thrombocytopenia in...

Objective The aim of this article is to discuss a protocol for obtaining platelet-rich plasma (PRP) and evaluate which factors, derived from its preparation method and from whole blood, modify PRP cytometry and coagulation time. Study design Whole blood, harvested from 50 rabbits, was centrifuged at 300g for 10 minutes. Supernatant was recentrifuged at 5000g for 5 minutes. PRP was clotted with calcium chloride. Whole blood and PRP cytometry were obtained through automatic measurement. The amount of erythrocyte-and platelet-poor plasma drawn from whole blood was measured. Hematocrit, platelet and leukocyte count, mean corpuscular volume (MCV) and mean platelet volume (MPV), mean, standard deviation, and median were also calculated at whole blood and PRP. PRP coagulation time was also analyzed. Mean values between groups were analyzed using Student t test. Correlations were evaluated using Pearson's correlation coefficient. The significance level was set at P Ͻ .05. A linear regression was performed to investigate the relationship among the correlated variables. Results From whole blood, 2.68 mL of erythrocytes and 5.72 mL of platelet-poor plasma (PPP) were removed. PRP platelet count was 2,324,080 cells/L. Whole blood hematocrit influenced the amount of cells and PPP removed, as well as PRP platelet count. PRP platelet count was dependent on whole blood hematocrit and platelet count, and does not interfere in PRP coagulation time. A linear interaction was confirmed between the variables that presented significant Pearson correlation. Conclusions The protocol evaluated produces a good PRP. Whole-blood parameters can predict PRP features. Wholeblood hematocrit is an important variable for PRP preparation and PRP cytometry characterization. PRP platelet count is dependent upon whole-blood platelet count.

The imbalance in clotting homeostasis, tending towards hypercoagulation, is recognized as the real barrier to the long-term survival of porcine xenografts in pig-to-primate xenotransplatation. The present study aimed to validate in primate blood the applicability of whole blood rotation thromboelastometry, performed by ROTEM®, which evaluates the characteristics of clot formation by dynamic monitoring.ROTEM® (Pentapharm GmbH, Munich, Germany) was used to investigate native coagulation (NATEM®), the intrinsic (INTEM®) and extrinsic (EXTEM®) pathways, the function of fibrinogen (FIBTEM®), and the presence of fibrinolysis in 40 naïve cynomolgus monkeys. Using classic validation approaches, the normal thromboelastographic profile was defined and the influence of haematocrit (Hct,%), platelet count (x109/L), fibrinogen (mg/dl), and factor VIII (FVIII,%) was evaluated.In all four (NATEM®, INTEM®, EXTEM®, FIBTEM®) assays considered, Clotting Time (CT, sec) and Clot Formation Time (CFT, sec) were shorter in primates than humans. Moreover, α-angle (°), Maximum Clot Firmness (MCF, mm), and MaxVel (mm/min) were also higher in primates than humans. No substantial difference was observed for Hct and platelet count between the two species. On the contrary, FVIII was higher in primates than in humans whereas, interestingly enough, fibrinogen levels were lower in monkeys than in humans.ROTEM® depicts a hypercoagulable profile in primates as compared to humans. Taken together these data suggest that, with regard to coagulation, xenotransplantation in cynos may represent a much more difficult situation than xenotransplantation in humans.

A multicentre, cross-sectional epidemiological survey was conducted to describe the health status of patients with type 1 Gaucher disease (GD1) in Spain. Patient data were collected retrospectively from clinical records. Therapeutic goals for seven clinical parameters were chosen as primary outcome measures. 108 GD1 patients (mean age 44.8 years; 53% male) were recruited from 28 hospitals. Ninety-five patients (88%) were receiving treatment for GD1. Hemoglobin concentration was the therapeutic goal with the highest level of achievement, being met by 105 of 108 patients (97%), followed by the goals for liver volume (86/98 patients; 88%), spleen volume (67/77 patients; 87%) and platelet count (81/108 patients; 75%). The goal for bone mineral density (BMD) was met by 48 of 75 patients (64%), and the goal for quality of life was met by 65 of 103 patients (63%). Bone pain was the parameter with the lowest level of achievement (goal met by 50/94 patients; 53%). The clinical information most often missing from patient records was the BMD Z-score (missing for 31% of patients). These data suggest that most Spanish GD1 patients have good control over hematological and visceral parameters, but there is a need to improve monitoring and treatment of GD-related bone disease.

BACKGROUND: An enhanced bacterial detection system (Pall eBDS) was developed that distinguishes itself from its predecessor (Pall BDS) by removal of the platelet (PLT)-retaining filter allowing for optimal bacterial transfer, modification of the culture tablet to reduce the confounding effects of respiring PLTs while enhancing bacterial growth, and facilitation of nutrients and gas exchange by agitating the sample pouch during incubation at 35°C. The objective was to evaluate the performance of the new eBDS.STUDY DESIGN AND METHODS: Leukoreduced whole blood–derived PLT concentrates (LR-PCs) and LR single-donor PLTs (LR-SDPs) were inoculated with 1 to 15 colony-forming units (CFUs) of bacteria per mL in studies of each of 10 bacterial species associated with fatal transfusion-transmitted bacterial infection. Immediately after inoculation and after 24 hours of storage at 22°C, samples of inoculated LR-PCs were aseptically transferred into the eBDS pouches. Pouches were then incubated for 24 hours at 35°C with agitation and oxygen concentration was then measured.RESULTS: Median inoculation levels ranged from 5 to 13 CFUs per mL for each species studied. No significant differences in oxygen concentration were found when comparing LR-PCs with LR-SDPs. When sampling occurred from the PLTs 24 hours after inoculation, all 280 cases (24-33 replicates of each species) were detected as contaminated by the device (100% sensitivity). No false-positives were obtained with 713 uninoculated PLT units.CONCLUSIONS: The eBDS demonstrated improved detection sensitivity in the range of 1 to 15 CFUs per mL with no observed false-positives compared to the original BDS (detection range 100 to 500 CFUs/mL) with no false-positives.

Purpose: To describe a new drilling system that allows the surgeon to obtain autologous living bone that, when associated with a plasma rich in growth factors (PRGF), can be used in bone grafting. Materials and Methods: Bone particles collected using both conventional and new drilling systems were analyzed by means of optic and electronic microscopy in 10 patients. Blood was collected from 43 volunteers and used to prepare PRGF. Quantitative aspects of the PRGF, including number of platelets and concentration of growth factors (insulin growth factor [IGF-I], transforming growth factor [TGF-␤1], platelet-derived growth factor [PDGF-AB], vascular endothelial growth factor [VEGF], hepatocyte growth factor [HGF], and epidermal growth factor [EGF]) were assessed. A demonstrative case study was presented. Results: Microscopic examination showed that the bone structure and the presence of living cells in the bone chips were conserved in all samples obtained from drilling at low speed, whereas material obtained by conventional drilling did not maintain these qualities. Mean counts for TGF-␤1 (55.27 ± 16.23 ng/mL), PDGF-AB (27.96 ± 12.13 ng/mL), VEGF (421.09 ± 399.0 pg/mL), EGF (455.49 ± 210.04 pg/mL), and HGF (605.70 ± 269.20 pg/mL) were significantly correlated with the number of platelets (590,000 ± 197,000 platelets/μL; P < .05). Discussion and Conclusion: The new drilling procedure was developed based on biologic criteria. The method may reduce damage to the host tissue and can be used to obtain a mass of living bone for subsequent grafting in association with autologous growth factors. This new procedure may present new possibilities for enhanced bone healing and needs to be evaluated in a clinical trial. (Technical Note) INT J ORAL MAX-ILLOFAC IMPLANTS 2007;22:138-145

Emerging issues in stimulating apheresis platelet donors with platelet growth factors, the relative costs of apheresis and random donor platelet concentrates, optimal platelet transfusion dose, and leucoreduction of platelet products have caused renewed debate regarding apheresis products vs. random, pooled concentrates. The future role of apheresis products in platelet transfusion therapy will in large part be determined by costs, which are increasingly recognized to be influenced by donor platelet count, apheresis yield, and platelet transfusion dose.

Dengue, the most prevalent arthropod-borne viral disease of humans, is caused by four serotypes of dengue virus (DENV 1-4). Although all four DENV serotypes cause a range of illness, defining precisely which clinical characteristics are associated with the distinct serotypes has been elusive. A cross-sectional study was conducted on 984 and 313 hospitalized children with confirmed DENV infections during two time periods, respectively, in the same hospitals in Nicaragua: a 3-year period (1999-2001) when DENV-2 accounted for 96% of the viruses identified, and the 2003 dengue season when DENV-1 predominated (87% of identified serotypes). When the two periods were compared, more shock (OR 1.91, 95% CI 1.35-2.71) and internal hemorrhage (OR 2.05, CI 1.16-3.78) were observed in the period when DENV-2 predominated, whereas increased vascular permeability was associated to a greater degree with the DENV-1 period (OR 2.36, CI 1.80-3.09). Compared with the DENV-2 period, the DENV-1 season was...

Purpose Platelet-rich plasma (PRP) harbors high concentrations of growth factors related to the promotion of wound healing. We evaluated the efficacy of PRP eyedrops in the treatment of persistent epithelial defects (PEDs). Methods Autologous PRP and autologous serum (AS) were prepared from whole blood. The concentrations of transforming growth factor (TGF)-b1, TGF-b2, epidermal growth factor (EGF), vitamin A and fibronectin in the PRP and AS were analyzed and compared. The corneal epithelial healing efficacy of PRP was compared with that of AS in patients with PED induced by post-infectious inflammation.

Babassu is the popular name of Orbignya phalerata Mart. (Arecaceae). The mesocarp flour obtained from their fruits has been used in Brazil as medicine in the treatment of pains, constipation, obesity, leukemia, rheumatism, ulcerations, tumors, inflammations and venous diseases. The effect of the chronic oral treatment with aqueous extract of babassu mesocarp (500 mg/kg day) on the number of platelets, the prothrombin time (PT), the activated partial thromboplastin time (aPTT), the nitric oxide (NO) production and the carrageenin-induced thrombosis was evaluated, using C57Bl/6 mice. The chronic oral treatment with babassu mesocarp induced an anti-thrombotic effect. There was a 88.9% reduction in the necrosis of the tail. This effect seems to be related to an increase in the ability of the macrophage to produce NO and to a slow coagulation process associated to an increase of 12.0 and 13.9% in PT and aPTT, respectively. However, the anti-thrombotic effect seems to be not related to alterations in the number of platelets. It is possible to conclude that the oral treatment with babassu mesocarp has a significant anti-thrombotic effect, which could justify the popular use of babassu mesocarp in the treatment of venous diseases. Meanwhile, this study suggests a potential use of babassu mesocarp as a prophylactic agent to avoid thrombosis events.

Effect of evening primrose oil (EPO) was assessed on coagulation parameters following 30 and 60 days
administration of 90, 180 and 360 μl/kg oil to healthy rabbits of either sex. There was significant increase in all
assays except Fibrinogen time. These effects might be due to inactivation or inhibition of factors affecting
coagulation. The intake of evening primrose oil also significantly decreased platelet count. Results of this study
suggest that evening primrose oil shows considerable anti-anticoagulant and anti-platelet activity in animals and
has potential to reduce cardiovascular morbidity and mortality.

New generation oxygenators with integrated arterial line filters have been marketed to improve the efficacy of cardiopulmonary bypass (CPB). Differences in designs, materials, coating surfaces, pore size of arterial filter, and static prime exist between the oxygenators. Despite abundant preclinical data, literature lacks clinical studies. From September 2010 to March 2011, 80 consecutive patients were randomized to CPB using Terumo Capiox FX25 (40 patients, Group-T) or Sorin Synthesis (40 patients, Group-S) oxygenators. Pressure drop and gas exchange efficacy were registered during CPB. Highsensitivity C-reactive protein (hs-CRP), white blood cells (WBCs), fluid balance, activated clotting time, international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, platelets (PLTs), serum albumin, and total proteins were measured perioperatively at different timepoints. Clinical outcome was recorded. Repeated measure analysis of variance and nonparametric statistics assessed between-groups and during time differences. The two groups showed similar baseline and intraoperative variables. No differences were recorded

In addition to reducing blood pressure, antihypertensive drugs should modify other atherosclerotic risk factors. One such risk factor is the prothrombotic state, which is characterised mainly by increased fibrinogen and plasminogen activator inhibitor-1 levels and abnormalities in platelet function. Platelet activity and aggregation potential can be estimated by measuring mean platelet volume (MPV). Serotonin plays a role in vasospasm and increased platelet aggregation capacity, and has been shown to increase MPV in vitro. However, serotonin levels and MPV have not been studied in the metabolic syndrome. We evaluated mean platelet volume (MPV) in patients with the metabolic syndrome, and compared the effects of doxazosin and amlodipine on MPV and serum serotonin level in patients with this condition. Thirty-eight patients who met the Adult Treatment Panel III criteria for the metabolic syndrome and 20 healthy controls were included in the study. Patients were randomised into two gro...

A 27-year-old woman was maintained in an isolated state for 131 days in Carlsbad Caverns, New Mexico. Her diet was vitamin D-depleted. Determinations on the effects of such isolation on levels and activities of peripheral blood cells that are important for hematological homeostasis and immunological function were carried out. Throughout the duration of the study, the percentage of lymphoid cells that expressed CD3, CD4, CD8, CD19, Leu 8, and other markers remained relatively constant although the absolute numbers of these cells varied. Although the percentage of natural killer (NK) cells did not vary, the activity of these cells did change. NK cell activity became elevated as the isolation study progressed. Production of interferon-gamma (IFN-gamma) in response to mitogen stimulation was higher than expected throughout the isolation periods, but returned to the normal range after termination of the isolation. Red and white cell counts dropped significantly upon entering isolation, but soon returned to normal.

The aim of this study was to investigate whether etamsylate produces equine platelet activation. In vitro and in vivo studies were designed in which seven and eight adult healthy horses were included, respectively. In the in vitro study, citrated blood was incubated with different concentrations of etamsylate, and P-selectin expression and annexin V binding were determined by flow cytometry. In the in vivo study, blood was collected before and 1 and 2 h after IV administration of etamsylate, and P-selectin expression was evaluated.

The Coulter LH 750 is a new haematology analyser with several new features: a count of nucleated red blood cells (NRBCs), automated WBC correction in presence of a flag indicating a cellular interference and a lower incidence of platelet or WBC interference flags when compared with the GEN.S, our current instrument. We had three main goals in our study: evaluating the LH 750 WBC counts when a GEN.S flag suggests a risk of WBC interference, ascertaining whether the platelet counts not flagged by the LH 750 were accurately assessed in samples flagged by the GEN.S and evaluating the NRBC assay provided by the LH 750. Flow cytometry, using CD45 and CD41, respectively for WBC and platelet labelling, was used as a reference method to assess the accuracy of the LH 750 counts. NRBC were identified by double labelling with propidium iodide (PI) and CD45, NRBCs being CD45-/PI+. A significant relationship was found between LH 750 and flow cytometric WBC counts, whether a WBC correction was made by the LH 750 (r = 0.9809, n = 54) or not (r = 0.9901, n = 23). A highly significant relationship was observed for platelets not only in the range from 0 to 450 x 10(9)/l (r = 0.981, n = 108) but also in cases of thrombocytopenia (range: 0-80 x 10(9)/l; r = 0.956, n = 51). In samples with NRBCs, the NRBC percentages given by the LH 750 and by flow cytometry were highly correlated (r = 0.977, n = 60) and WBC counts were accurate. In conclusion, the reduction in flagging by the LH 750, the accuracy of the results, and the availability of a NRBC count, constitute major advantages.

We have developed an assay of thrombin generation in clotting whole blood. Because our goal was to study patients with red blood cell diseases that are associated with thrombosis, the initial evaluation of this assay analysed the effect of the haematocrit and haemolysate on the total amount of thrombin activity generated and the maximal concentration of thrombin achieved. Both of these parameters were proportional to the haematocrit throughout a wide range of clinically relevant cell concentrations. Red cell lysate also augmented thrombin generation. Because this effect was removed by filtration of the lysate, we propose that it was related to red cell microparticles.

The purpose of this study was to determine predictors of bleeding complications after current rescue coronary interventions including stenting and adjunctive platelet inhibitors. Previous studies of rescue angioplasty for thrombolytic failure have identified variable rates of bleeding complications with balloon angioplasty alone. Although coronary stents and glycoprotein 2b/3a inhibitors have been shown to improve outcome in a wide variety of coronary interventions, the impact of these therapies on bleeding complications after rescue coronary intervention has not been determined. From 1996 through 1998, we treated 108 consecutive patients with rescue coronary intervention (defined as attempted coronary intervention within 12 hours of thrombolysis for ongoing symptoms or electrocardiogram [ECG] changes) including conventional percutaneous transluminal coronary artery (PTCA), stenting (n = 45), and glycoprotein 2b/3a inhibitor use (n = 31). In-hospital clinical outcomes were obtained ...

Standards and regulations require measurement of pH as an apheresis platelet (PLT) component quality monitor. The usefulness of this quality control (QC) measure was investigated. QC data were retrospectively reviewed for apheresis PLTs collected over 4.5 years. Three collection devices were used, the Amicus (Baxter), the CS-3000 Plus (Baxter), and the MCS+ LN9000 (Haemonetics). Each month, four components from each instrument were sampled. PLT counts and component volume were measured immediately after collection, and pH, after 5 days of storage. A total of 668 products were studied. pH decreased as PLT concentration increased (r(2) = 0.129, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) and as component volume decreased (r(2) = 0.086, p = 0.02). PLT concentration and volume, however, were poor predictors of a low pH. Apheresis instrument type affected pH. The 216 components collected with use of the CS-3000 device had a lower pH than components from the other two instruments. Only 13 components had a pH value less than the acceptable level of 6.2, 12 of which were collected with the CS-3000. For newer-model blood cell separators, pH measurements do not provide information that might identify a manufacturing problem. Because factors that influence pH are controlled or monitored for each component, evaluation of pH on a sample group provides an indication of the quality of specific component only, rather than an effective monitor of the quality of the manufacturing process.

Each individual has an inherent variable risk of bleeding linked to genetic or acquired abnormal platelet number or platelet dysfunction. In contrast, it is less obvious that the variability of platelet phenotypes (number, mean platelet volume, function) may contribute to the variable individual risk of thrombosis. Interindividual variability of platelet indices or function may be either due to acquired factors, such as age, sex, metabolic variables, smoke, dietary habits, and ongoing inflammation, or due to genetic factors. Acquired variables explain a small portion of the heterogeneity of platelet parameters. Genetic factors, instead, appear to play a major role, although a consistent portion of such a genetic variance has not yet been attributed to any specific genetic factor, possibly due to the high number of DNA loci potentially involved and to the limited effect size of each individual SNP. A portion of variance remains thus unexplained, also due to variability of test performance. A major contradiction in present platelet knowledge is, indeed, the difficulty to reconcile the universally accepted importance of platelet indices or function and the lack of reliable platelet parameters in cardiovascular risk prediction models. Trials on antiplatelet drugs were generally designed to select a homogeneous sample, whose results could be applied to an &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;average subject,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; tending to exclude the deviation/extreme values. As the current indications for antiplatelet treatment in primary or secondary prevention of ischemic vascular disease still derive from the results of such clinical trials where platelet function and its variability was not investigated, we cannot at present rely upon any current platelet test to either initiate, or monitor, or modify or stop treatment with any antiplatelet drug. Evidence is, however, increasing that traditional platelet aggregometry and other more recently developed platelet function assays could be useful to optimize antiplatelet therapy and to predict major adverse cardiac events.The observation of interindividual differences in platelet response to antiplatelet drugs has enlarged the spectrum and the possible clinical relevance of the variability of platelet indices or function. The development of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;personalized medicine&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; will benefit from the concepts discussed in this chapter.

The Beckman Coulter UniCel Ò DxH 800 is a hematology analyzer incorporating new electronic and mechanical design with advanced algorithm technology to perform CBC, white blood cell (WBC) differential, nucleated red blood cell (NRBC), and reticulocyte analysis. Evaluation of this instrument was performed in our 800-bed tertiary care hospital and specifically centered upon the correlation of WBC, NRBC, and platelet (PLT) enumeration when compared to a predicate analyzer, the Coulter Ò LH 780, and flow cytometry (FCM) reference methods. Of particular interest were those samples with morphologically confirmed interference and extreme leukocytosis (evaluated with respect to red blood cell parameter correction). The sample set (n = 272) consisted of morphologically normal and hematologically abnormal patients. Correlation of the WBC, PLT, and NRBC showed r 2 values of 0.994, 0.985, and 0.910 for the DxH 800 vs. FCM, respectively. The presence of interfering particles did not affect the accuracy of the DxH 800 with respect to WBC counts. The DxH 800 showed accurate PLT and NRBC counts in the clinically significant low range when compared to FCM. Compared to the LH 780, flagging rates were significantly reduced (NRBC flag), or equivalent (WBC, PLT flag) on the DxH 800. The DxH 800 demonstrated higher sensitivity and specificity for PLTs and NRBCs and achieved a lower NRBC false negative rate compared to the LH 780. The UniCel Ò DxH 800 represents a significant improvement to previous impedance analyzers in accurately detecting the presence of NRBCs at counts >1/100 WBC. Furthermore, it provides accurate PLT and WBC counts in the presence of interference and improved NRBC flagging efficiency when compared to the LH 780. Correction of red blood cell parameters is appropriate and accurate in cases of extreme leukocytosis.