A longitudinal assessment of non-invasive biomarkers to diagnose and predict cystic fibrosis-associated liver disease.

BACKGROUND & AIMS: A practical, inexpensive, and non-invasive biomarker of liver fibrosis is needed as a reliable screening test for cystic fibrosis-associated liver disease (CFLD). Studies have shown the utility of AST to Platelet Ratio Index (APRI), fibrosis index based on 4 factors (FIB-4), and gamma-glutamyl transferase (GGT) as good biomarkers for identifying CFLD. The goal of the study was to evaluate the effectiveness of APRI, FIB-4, AST/ALT ratio, platelet count, GGT, and GGT platelet ratio (GPR) in predicting CFLD development. METHODS: Data was collected from CF Foundation Patient Registry for patients aged 3-21 years at Johns Hopkins from January 1, 2002 to December 31, 2014. Collected data included demographic characteristics, presence of splenomegaly, hepatomegaly, ascites, and variceal bleeding, AST, ALT, GGT, platelet count, and FEV1. The sensitivity and specificity of each biomarker were analyzed and reported by the area under receiver operating characteristic (AUROC) curve. RESULTS: By the end of the study, 144 "healthy" CF, 12 CFLD, 19 CF-associated pulmonary disease (CFPD), and 4 CFLD with CFPD cases were identified. APRI scores were higher in CFLD, 0.85 versus 0.28 in "healthy" CF and 0.23 in CFPD groups (p<0.001). GPR had the highest AUROC curve at 0.91. CONCLUSIONS: GPR, GGT, APRI score, and platelet count were potentially useful biomarkers while FIB-4 did not predict CFLD development. Cost-effectiveness studies are needed to analyze the utility of these biomarkers in clinical practice.

The role of the platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio in the prediction of length and cost of hospital stay in patients with infected diabetic foot ulcers: A retrospective comparative study.

OBJECTIVE: The aim of this study was to determine the role of new inflammatory markers, including the platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR), in the prediction of length and cost of hospital stay in patients with infected diabetic foot ulcers (DFUs). METHODS: A total of 78 patients with DFUs who were admitted to our endocrinology clinic between January 2016 and July 2017 were included. Patients were then divided into three groups according to the Wagner DFU classification system: group 1: 18 patients with grade 2 DFU (11 men, 7 women; mean age = 57.5±7 years); group 2: 44 patients with grade 3 DFU (18 men, 26 women; mean age = 59.7±8.7 years); and group 3: 16 patients with grade 4 DFU (10 men, 6 women; mean age = 59.9±11.6 years). Laboratory findings were retrospectively obtained from hospital records; the PLR and NLR were calculated in all groups. Length and cost of hospital stay were recorded. Hospital costs were estimated in Turkish Lira (TL) based on the evaluation of glucose regulation, wound care, and antibiotic treatment. RESULTS: The mean NLR was significantly lower in group 1 (2.8±0.9) than in group 2 (6.0±5.2; p=0.017) and group 3 (6.9±5.3; p=0.011). The mean PLR was significantly lower in group 1 (140.8±42.6) than in group 3 (222.1±95.5; p=0.006). The mean length of stay was 7.9±2.7 days in group 1, 15.0±8.9 days in group 2, and 12.5±8.9 days in group 3. The mean cost was 1,310.8±500 TL in group 1, 2,966.9±2105 TL in group 2, and 3,488.1±3603.1 TL in group 3. Length and cost of stay were both significantly lower in group 1 than in groups 2 and 3 (p=0.011 and p=0.002, respectively). Comparative results showed that the length and cost of hospital stay increased with increasing severity of DFUs. Furthermore, correlation analyses demonstrated no correlation of length of stay with PLR and NLR but an obvious correlation between cost of stay and PLR (r=0.412; p<0.001). Additionally, there was no correlation between cost of stay and NLR (r=0.158, p>0.05). CONCLUSION: The PLR is inflammatory marker that can be measured by an inexpensive and easily accessible test and can aid in the prediction of length and cost of hospital stay in patients with DFUs. LEVEL OF EVIDENCE: Level III, Therapeutic study.

Usefulness of noninvasive methods including assessment of liver stiffness by 2-dimensional shear wave elastography for predicting esophageal varices.

BACKGROUND: The aim of this study was to predict the presence of esophageal varices (EVs) by noninvasive tools combined with 2-dimensional shear wave elastography (2D-SWE), and to compare the diagnostic capabilities of 2D-SWE with those of transient elastography (TE). METHODS: Between January 2015 and December 2017, 289 patients with compensated advanced chronic liver disease (cACLD) who underwent consecutive 2D-SWE and EGD were enrolled. Capabilities for predicting the presence of EVs of 2D-SWE and models combining 2D-SWE with other noninvasive tools (modified LS-spleen-diameter-to-platelet-ratio score [mLSPS], platelet-spleen ratio score) were compared. A subgroup analysis was performed on 177 patients who also underwent simultaneous TE. RESULTS: The area under receiver operating characteristics (AUROCs) for detecting EVs for 2D-SWE alone vs. mLSPS, which included 2D-SWE, were 0.757 (95% confidence interval [CI], 0.701-0.810) and 0.813 (95% CI, 0.763-.857), respectively. The AUROCs for predicting varices needing treatment (VNT) for 2D-SWE and mLSPS were 0.712 (95% CI, 0.621-0.738) and 0.834 (95% CI, 0.785-0.875), respectively. For the 195 patients who underwent simultaneous TE and 2D-SWE, no differences in diagnostic performance were observed. CONCLUSIONS: The diagnostic performance of 2D-SWE is similar to that of TE for predicting the presence of EVs. The mLSPS, which includes 2D-SWE, seemed to be useful for predicting EVs.

Comparison of platelet function tests for the in vitro quality assessment of platelet concentrates produced under real-life conditions.

Platelet quality in different platelet concentrates (PCs) has been the subject of several studies. Nonetheless, there is a lack of robust data on the correlation and agreement among platelet function tests as a prerequisite for the association of PC functionality in vitro with platelet function in vivo post PC transfusion. The purpose of our study was to correlate a larger panel of platelet function assays in PCs and to assess whether the methods agree sufficiently and can be used interchangeably. Twelve apheresis platelet concentrates in plasma (APC), 16 pooled platelet concentrates in plasma (PPC), and 12 PPC in T-sol (PPCA) were examined on days 1 and 4 after production. PCs were tested for platelet count, light transmission aggregation (LTA) induced by ADP, collagen, or TRAP; platelet ATP release induced by collagen; and spontaneous and ADP and TRAP-induced increase in CD62P and PAC1 expression measured by flow cytometry. All tests were performed in undiluted platelet-rich plasma, recalcified and mixed with an inhibitor of factor Xa and thrombin. Most platelet function parameters correlated significantly with each other, but agreement among methods was insufficient. A proper inverse correlation was observed between ADP-induced LTA and spontaneous platelet activation assessed by CD62P expression (r = -0.61, p < 0.0001). Spontaneous CD62P correlated also significantly with spontaneous PAC1 (r = 0.69, p < 0.0001) and inversely with TRAP-induced CD62P expression (r = -0.86, p < 0.0001). We found significant correlations among all flow cytometric assays measuring platelet CD62P and PAC1 expression induced by ADP or TRAP. Subsequent Bland Altman analysis revealed insufficient agreement between methods. With one exception (collagen-induced LTA compared with TRAP-induced LTA, percentage error = 16%) the limits of agreement expressed as percentage error exceeded the chosen acceptable difference of 30%. In APC, platelet count was 41% and 44% higher, respectively, than in PPC and PPCA (p < 0.0001). Spontaneous CD62P and PAC1 expression were significantly greater, and ADP-induced aggregation and agonist-induced increase in CD62P and PAC1 were significantly lower in PPCA compared to APC and PPC on day 4 of storage. ADP and TRAP-induced CD62P and PAC1 activatability fell significantly during storage between day 1 and day 4 in APC and PPCA, but not in PPC. In conclusion, different platelet function tests capture different aspects of platelet function and do not correlate and agree sufficiently to be used interchangeably.

Impact of a negative D-dimer result on the initial assessment of acute aortic dissection.

BACKGROUND: D-dimer shows high sensitivity but low specificity for the diagnosis of acute aortic dissection (AAD). Previous reports indicated that negative D-dimer patients have shorter dissection length. However, whether patients with negative D-dimer results have a good prognosis is unknown. This study aimed to elucidate the clinical characteristics and implications of a negative D-dimer result on AAD diagnosis. METHODS: The study group comprised 126 patients (71 males, 55 females; mean age, 69 ±â€¯11 years) with AAD admitted to our hospital between April 2009 and March 2015. Blood samples on presentation were used for D-dimer measurement. Clinical characteristics and outcomes were assessed. RESULTS: Nine (7.1%) and 117 (92.9%) exhibited negative and positive D-dimer results, respectively. The negative group showed a significantly lower extension score and a higher platelet count than the positive group. Multivariate analysis demonstrated that platelet count (odds ratio, 1.31 (1.09-1.58), p = 0.003) and extension score (odds ratio, 0.56 (0.33-0.96), p = 0.03) were significantly related to a negative result. Notably, 44% of patients in the negative group had type A dissection and 33% underwent an emergency operation due to cardiac tamponade. CONCLUSION: We found that high platelet count and low extension score were independent factors related to a negative D-dimer result. Even if the length of the dissection is short, an emergency operation is necessary in some patients with a negative D-dimer result. Physicians should recognize that a negative D-dimer result alone cannot exclude patients with fatal AAD conditions.

Rate of bleeding-related episodes in elderly patients with primary immune thrombocytopenia: a retrospective cohort study.

OBJECTIVE: Immune thrombocytopenia (ITP) is characterized by low platelet counts and a tendency toward increased bleeding and bruising. We aimed to describe bleeding frequency and use of rescue ITP therapy to treat or prevent bleeding in elderly ITP patients in a real-world setting. METHODS: Using Medicare 20% sample data, 2007-2012, we identified elderly (ages ≥67 years) Medicare fee-for-service enrollees diagnosed with primary ITP between 1 January 2009 and 30 September 2012. Bleeding-related episodes (BREs) were defined as ≥1 bleeding event or use of ITP therapies commonly considered for rescue or emergency therapy. BRE rates were examined for the cohort overall, by time since ITP onset, and by splenectomy status. Patients were followed from ITP onset until the earliest of death, disenrollment from fee-for-service coverage, or 31 December 2012. RESULTS: We identified 3007 elderly patients diagnosed with primary ITP (mean [SD] age: 79.6 [7.5] years; 55% female); 2178 (72%) experienced at least one BRE (8867 BREs); 92 (3%) underwent splenectomy. Nearly half of BREs were defined by rescue therapy use alone. The overall rate was 1.72 BREs per patient-year (95% CI; 1.68-1.75); rates were higher during the first 3 months after ITP onset and after splenectomy. CONCLUSION: Elderly ITP patients experienced about two BREs per patient-year after ITP onset. Most patients experienced at least one BRE. These real-world results demonstrate the importance of examining both bleeding and use of rescue or emergency ITP therapy in the assessment of disease burden in elderly patients with ITP.

Assessment of the Reliability of the Sysmex XE-5000 Analyzer to Detect Platelet Clumps.

OBJECTIVE: Platelet counts generated by automated analyzers on blood specimens that contain platelet clumps are often inaccurate and require verification by blood-smear review. In this study, we assessed the reliability of the Sysmex XE-5000 instrument to detect platelet clumps. METHOD: We reviewed automated complete blood count (CBC) results and the findings of the microscopic review of corresponding blood smears of 600 blood specimens specifically selected from the routine laboratory workload. The sensitivity, specificity, efficiency, positive predictive value (PPV), and negative predictive value (NPV) of its 2 platelet-associated flags (abnormal platelet-size distribution [PAD] flag and platelet-clumps [CLP] flag) were determined. RESULTS: The respective values for the sensitivity, specificity, efficiency, and PPV were 42%, 83%, 63%, and 1% for the PAD flag and 57%, 99%, 78%, and 37% for the CLP flag. The NPV was 100%. CONCLUSION: The overall reliability of the CLP flag is superior than that of the PAD flag but there is room for further improvement.

Pre-operative labs: Wasted dollars or predictors of post-operative cardiac and septic events in orthopaedic trauma patients?

PURPOSE: As US healthcare expenditures continue to rise, there is significant pressure to reduce the cost of inpatient medical services. Studies have estimated that over 70% of routine labs may not yield clinical benefits while adding over $300 in costs per day for every inpatient. Although orthopaedic trauma patients tend to have longer inpatient stays and hip fractures have been associated with significant morbidity, there is a dearth of data examining pre-operative labs in predicting post-operative adverse events in these populations. The purpose of this study was to assess whether pre-operative labs significantly predict post-operative cardiac and septic complications in orthopaedic trauma and hip fracture patients. METHODS: Between 2006 and 2013, 56,336 (15.6%) orthopaedic trauma patients were identified and 27,441 patients (7.6%) were diagnosed with hip fractures. Pre-operative labs included sodium, BUN, creatinine, albumin, bilirubin, SGOT, alkaline phosphatase, white count, hematocrit, platelet count, prothrombin time, INR, and partial thromboplastin time. For each of these labs, patients were deemed to have normal or abnormal values. Patients were noted to have developed cardiac or septic complications if they sustained (1) myocardial infarction (MI), (2) cardiac arrest, or (3) septic shock within 30 days after surgery. Separate regressions incorporating over 40 patient characteristics including age, gender, pre-operative comorbidities, and labs were performed for orthopaedic trauma patients in order to determine whether pre-operative labs predicted adverse cardiac or septic outcomes. RESULTS: 749 (1.3%) orthopaedic trauma patients developed cardiac complications and 311 (0.6%) developed septic shock. Multivariate regression demonstrated that abnormal pre-operative platelet values were significantly predictive of post-operative cardiac arrest (OR: 11.107, p=0.036), and abnormal bilirubin levels were predictive (OR: 8.487, p=0.008) of the development of septic shock in trauma patients. In the hip fracture cohort, abnormal partial thromboplastin time was significantly associated with post-operative myocardial infarction (OR: 15.083, p=0.046), and abnormal bilirubin (OR: 58.674, p=0.002) significantly predicted the onset of septic shock. CONCLUSIONS: This is the first study to demonstrate the utility of pre-operative labs in predicting perioperative cardiac and septic adverse events in orthopaedic trauma and hip fracture patients. Particular attention should be paid to haematologic/coagulation labs (platelets, PTT) and bilirubin values. LEVEL OF EVIDENCE: Prognostic Level II.

Red cell volume distribution width-to-platelet ratio in assessment of liver fibrosis in patients with chronic hepatitis B.

BACKGROUND & AIMS: Precise assessment of liver fibrosis is necessary in patients with chronic liver disease. We investigated the performance of red cell volume distribution width-to-platelet ratio for the assessment of liver fibrosis in patients with chronic hepatitis B. METHODS: A total of 482 consecutive patients with chronic hepatitis B who underwent liver biopsy between October 2005 and May 2014 were recruited. Liver stiffness was measured using transient elastography. FIB-4 score, red cell volume distribution width-to-platelet ratio and the aspartate aminotransferase-to-platelet ratio index were also assessed. RESULTS: A total of 271 (56.2%) patients were males. The median age was 44 years. F1, F2, F3 and F4 fibrosis stages were identified in 68 (14.1%), 137 (28.4%), 64 (13.3%) and 213 (44.2%) of the patients respectively. The mean red cell volume distribution width-to-platelet ratio increased with liver fibrosis severity: F1, 0.065; F2, 0.077; F3, 0.097 and F4, 0.121 (P < 0.01). The area under the receiver operating characteristic curve of the red cell volume distribution width-to-platelet ratio for predicting significant fibrosis (≥F2) was 0.747. This result was inferior to transient elastography (0.866, P = 0.004), but comparable to FIB-4 (0.782, P = 0.427) and aspartate aminotransferase-to-platelet ratio index (0.716, P = 0.507). The area under the receiver operating characteristic curve of red cell volume distribution width-to-platelet ratio for predicting cirrhosis (F4) was 0.811, which was inferior to liver stiffness (0.915, P < 0.001), but comparable to FIB-4 (0.804, P = 0.805) and superior to aspartate aminotransferase-to-platelet ratio index (0.680, P < 0.001). CONCLUSIONS: The accuracy of red cell volume distribution width-to-platelet ratio was acceptable for the assessment of liver fibrosis in patients with chronic hepatitis B. When transient elastography is not available, red cell volume distribution width-to-platelet ratio assessment is a simple method that can be used to reduce the need for liver biopsy.

Las trombopoyetinas en el tratamiento de la púrpura trombocitopénica inmunitaria y otras trombocitopenias / Thrombopoietines in the treatment of the thrombocytopenic purpura and other thrombocytopenics

La purpura trombocitopénica inmunitaria y las trombocitopenias secundarias representan condiciones patológicas graves cuyo tratamiento plantea diversos grados de dificultad. La aproximación terapéutica convencional ha sido la administración de esteroides, la esplenectomía y el uso de inmunoglobulina intravenosa u otros tipos de anticuerpos (e.g., anti-D). La mejor comprensión de la fisiología y fisiopatología de la trombopoyesis aunado a los avances en biología molecular ha permitido el desarrollo de una nueva aproximación terapéutica, la aplicación de las trombopoyetinas sintéticas o no inmunogénicas. Dentro de este grupo resaltan dos compuestos: el romiplostin (una proteína de fusión) y el eltrombopag (un compuesto sintético de bajo peso molecular). Ambas se encuentran disponibles comercialmente. Los estudios clínicos indican que estos medicamentos tienen un efecto satisfactorio en el tratamiento de las trombocitopenias, particularmente en los casos refractarios a los tratamientos convencionales.

Immune thrombocytopenic purpura and the secondary thrombocytopenias are conditions potentially severe with diverse degrees of treatment difficulties. Steroids administration, splenectomy and the use of intravenous immunoglobulin and other antibodies (e.g., anti-D) had been the conventional therapy. The better understanding of the thrombopoiesis physiology and physiopathology togetter with the biology advances have permitted the development of a new terapheutic approach: the use of synthetic or nonimmunogenic thrombopoietines. Among this group highlights composites: romiplostim (a fusion protein) and eltrombopag (a synthetic composite with low molecular wheigt). Both are already available and produce a satisfactory effect particularly in nonrespondent cases to the conventional treatment.

Using lean techniques to define the platelet (PLT) transfusion process and cost-effectiveness to evaluate PLT dose transfusion strategies.

BACKGROUND: Platelet (PLT) doses of 1.1 × 10(11), 2.2 × 10(11), and 4.4 × 10(11) /m(2) body surface area are equally effective in preventing bleeding. These different dose strategies involve different numbers of transfusions. We conducted a cost analysis of three separate PLT dose therapies. STUDY DESIGN AND METHODS: A process map of preparation and administration of a PLT transfusion identified 46 steps (23 steps in the blood bank and 23 steps on the care unit). Time studies were conducted for these 46 steps. Supply costs and personnel costs were estimated based on time studies. We conducted a cost analysis of three separate treatment regimes involving 16 transfusions per patient for the low-dose, 12 transfusions for medium-dose, and eight transfusions for high-dose regimes. RESULTS: The time and the cost of the transfusion process for the blood bank were 32.41 minutes and $21.93 per unit, and for the patient care unit, 58.36 minutes and $57.71 per unit. The total cost for a course of PLT therapy per patient ranged from $4503.77 to $7014.59 for three different PLT doses. For a simulated bone marrow transplantation unit with 259 patients annually, there would be approximately a $700,000 difference among the clinically equivalent low-, medium-, and high-dose treatment options. CONCLUSIONS: The overall cost of transfusion therapy is more influenced by the cost of the product than the cost of providing the transfusion. Depending on the cost adjustment by the supplier for different doses of PLTs, a low-dose transfusion strategy can be less costly.

The accuracy of platelet counting in thrombocytopenic blood samples distributed by the UK National External Quality Assessment Scheme for General Haematology.

A knowledge of the limitations of automated platelet counting is essential for the effective care of thrombocytopenic patients and management of platelet stocks for transfusion. For this study, 29 external quality assessment specimen pools with platelet counts between 5 and 64 × 10(9)/L were distributed to more than 1,100 users of 23 different hematology analyzer models. The same specimen pools were analyzed by the international reference method (IRM) for platelet counting at 3 reference centers. The IRM values were on average lower than the all-methods median values returned by the automated analyzers. The majority (~67%) of the automated analyzer results overestimated the platelet count compared with the IRM, with significant differences in 16.5% of cases. Performance differed between analyzer models. The observed differences may depend in part on the nature of the survey material and analyzer technology, but the findings have implications for the interpretation of platelet counts at levels of clinical decision making.

Multiple electrode whole blood aggregometry, PFA-100, and in vivo bleeding time for the point-of-care assessment of aspirin-induced platelet dysfunction in the preoperative setting.

BACKGROUND: Acquired platelet dysfunction due to aspirin ingestion may increase bleeding tendency during surgery. Thus, we examined the diagnostic accuracy of in vivo bleeding time (BT) and 2 platelet function assays for the preoperative assessment of a residual antiplatelet effect in patients treated with aspirin. METHODS: Consecutive patients scheduled for surgery were prospectively enrolled in this study. The patients' last aspirin ingestion had occurred within the previous 48 hours before blood sampling in the "full aspirin effect" group, between 48 and 96 hours before in the "variable aspirin effect" group, and >96 hours before in the "recovered aspirin effect" group. The control group had not taken any aspirin. Multiple electrode aggregometry, platelet function analyzer (PFA)-100, and in vivo BT were performed to assess the effects of aspirin. One-way analysis of variance on ranks with a post hoc multiple-comparison procedure (Dunn) was used to detect differences among the groups. Categorical data were compared using the z test. Receiver operating characteristic (ROC) curves were created to determine the diagnostic accuracy of the platelet function assays investigated. The area under the ROC curve (AUC), sensitivity, and specificity of the assays were calculated. The level of statistical significance was set at P < 0.05. RESULTS: Three hundred ninety-four patients were included in the analysis (133 control and 261 aspirin-treated patients). All 3 methods were able to detect the antiplatelet effect of aspirin in the full aspirin effect group. Furthermore, no difference in the measurement values between the recovered aspirin effect and control group was found, irrespective of the assay performed. Measurement values in the variable aspirin effect group were different from those of the control group in the ASPItest using multiple electrode aggregometry and COL-EPI using PFA-100 but not in BT. ROC analysis showed the highest diagnostic accuracy in excluding the residual aspirin effect in the ASPItest (AUC 0.81, P < 0.001), followed by COL-EPI (AUC 0.78, P < 0.001) and BT (AUC 0.56, P = 0.05). The cutoff value of 53 U in the ASPItest excluded the effect of aspirin with a sensitivity of 88% and specificity of 71%. CONCLUSIONS: The full therapeutic antiplatelet effects of aspirin can be expected within 48 hours of the patient's last aspirin ingestion. Platelet function recovered in our study if aspirin cessation occurred >96 hours (4 days) before; thus, in these patients, preoperative platelet function testing is not useful. To quantify any residual aspirin effect in patients who ceased their intake of aspirin between 48 and 96 hours before surgery, the ASPItest might have the highest diagnostic accuracy.

[Assessment of an immature platelet fraction (IFP%) in the diagnosis of thrombocytopenia]. / Valeur du pourcentage de plaquettes réticulées dans le diagnostic étiologique d'une thrombopénie.

Reticulated platelets are young platelets containing mRNA. They reflect the rate of thrombopoesis. The aim of this study was to evaluate the reliability of the percentage of reticulated platelets (IPF%) as a diagnostic test for thrombocytopenia pathogenesis. IPF% was measured using XE 2100 Sysmex. An IPF% reference range in 52 healthy individuals was established as 1-4.5% with a median 2.2%. In all the 13 patients with idiopathic thrombocytopenic purpura IPF% was increased (median 11.8, range 5.3-54.3%). Only 7 out of 18 patients with disseminated intravascular coagulation had high IPF% (median 5.4%, range 2.9-14.1%). Surprisingly, IPF% was increased in 17 out of 22 patients with acute leukaemia (median 9.7%, range 0.9-41.9%). In CIVD, IPF% values correlated with the severity of the illness. Increased values in acute leukaemia could not be explained by non specific staining but by delayed maturation of reticulated platelets. A high IPF% does not substantiate hyperdestructive thrombocytopenia but a diagnosis of idiopathic thrombocytopenic purpura should be questioned if IPF% is not raised.

Optimal combinations of ultrasound-based and serum markers of disease severity in patients with chronic hepatitis C.

Combinations of noninvasive markers may improve discrimination of chronic liver disease severity. The aims of this study were to compare four validated serum and ultrasound-based markers of hepatic disease severity head-to-head with liver biopsy and to assess optimal combinations with consideration of cost. A total of 67 patients with biopsy-proven chronic hepatitis C underwent all four techniques on the same visit [aspartate aminotransferase (AST) to platelet ratio index (APRI); Enhanced Liver Fibrosis (ELF) panel; transient elastography (TE) and ultrasound microbubble hepatic transit times (HTT)]. Markers were combined according to increasing financial cost and ordinal regression used to determine contributions. APRI, ELF, TE and HTT predicted cirrhosis with diagnostic accuracy of 86%, 91%, 90% and 83% respectively. ELF and TE were the most reliable tests with an intra-class correlation of 0.94 each. Either ELF or TE significantly enhanced the prediction of fibrosis stage when combined with APRI, but when combined together, did not improve the model further. Addition of third or fourth markers did not significantly improve prediction of fibrosis. Combination of APRI with either ELF or TE effectively predicts fibrosis stage, but combinations of three or more tests lead to redundancy of information and increased cost.

Flow cytometric assessment of platelet aspirin resistance using light scattering.

BACKGROUND: A simple and reliable assay is needed for the prediction of the clinical efficacy of antiplatelet aspirin therapy. We have devised another method for the evaluation of platelet function and aspirin resistance (AR), via conventional flow cytometry (FCM). METHODS: To devise an optimized protocol for the assessment of platelet AR, various analytic variables of FCM were investigated. Using this devised protocol, AR was assessed in healthy subjects as an example. RESULTS: The protocol utilized herein is as follows: citrate-anticoagulated platelet-rich plasma was mixed 1:1 with HEPES-buffered saline in two tubes, one of which is treated with aspirin. During the acquisition of FCM, arachidonate is added to the tube. The response of the aspirin-treated platelets is then compared with those of nontreated ones on a time/forward scatter plot. In the 61 total subjects, none was identified as aspirin resistant by this assay. CONCLUSIONS: Using light scattering, platelet aggregation and aspirin's antiplatelet effects can be readily and cost-effectively detected. According to this assay, biochemical AR appears to be rare. This new protocol may prove useful in a clinical setting or as a research tool.

Hemostatic function in healthy pregnant and preeclamptic women: an assessment using the platelet function analyzer (PFA-100) and thromboelastograph.

BACKGROUND: The PFA-100 is a point-of-care platelet function analyzer which measures the speed of formation of a platelet plug in vitro, expressed as closure time (CT) in seconds. This device could potentially be used to assess primary hemostasis prior to regional anesthesia. In this prospective, observational study we sought to establish 95% reference intervals for PFA-100 and Thromboelastograph (TEG) values for our normal pregnant population, before comparing the PFA and TEG in measuring platelet function in preeclamptic and healthy pregnant women at term, using confidence interval analysis and analysis of variance. METHODS: Routine hematologic and coagulation tests were performed along with von Willebrand Factor, CT, and TEG measurements. Results are expressed as mean (sd). RESULTS: Increased severity of preeclampsia was associated with increasing prolongation of CT, even in the presence of normal platelet counts. In severe preeclampsia, the PFA-100 CT (mean (sd): 155 (65) s) exceeded the 95% reference interval of the control group (70-139 s). In contrast, TEG maximum amplitude (MA) in severe preeclampsia (mean (sd): 71 (8) mm) remained within the 95% reference interval for MA in normal pregnancy (64-82 mm). CONCLUSION: We conclude that impairment of primary hemostatic function with increasing severity of preeclampsia was recorded by the PFA-100 but not the TEG.

Assessment of an immature platelet fraction (IPF) in peripheral thrombocytopenia.

A new automated method to reliably quantify reticulated platelets, expressed as the immature platelet fraction (IPF), has been developed utilizing the XE-2100 blood cell counter with upgraded software (Sysmex, Kobe, Japan). The IPF is identified by flow cytometry techniques and the use of a nucleic acid specific dye in the reticulocyte/optical platelet channel. The clinical utility of this parameter was established in the laboratory diagnosis of thrombocytopenia due to increased peripheral platelet destruction, particularly autoimmune thrombocytopenic purpura (AITP) and thrombotic thrombocytopenic purpura (TTP). Reproducibility and stability results over 48 h were good. An IPF reference range in healthy individuals was established as 1.1-6.1%, with a mean of 3.4%. Patients in whom platelet destruction might be abnormal, were studied and two of these patients followed serially during the course of treatment. The IPF was raised in several disease states. The most significant increases in IPF values were found in patients with AITP (mean 22.3%, range 9.2-33.1%) and acute TTP (mean 17.2%, range 11.2-30.9%). Following patients during treatment demonstrated that as the platelet count recovered the IPF% fell. These results show that a rapid, inexpensive automated method for measuring the IPF% is feasible and should become a standard parameter in evaluating the thrombocytopenic patient.

Platelet count assessment from peripheral blood smear (PBS).

OBJECTIVE: To visually count platelets in a peripheral blood smear and compare with an automated machine platelet count. METHODS: Thirty-five peripheral blood smears were made from blood specimens counted on an automated blood cell machine: twenty-three thrombocytopenic specimens, 1 with high platelet count and 11 with normal counts. Ten and 25 high-power fields were microscopically averaged and then multiplied by 15,000 and 20,000 to arrive at a platelet count in 1,000 per microliter. Comparisons between visual and machine counts were drawn. RESULTS: There was fair concordance in 27 specimens. In three specimens underestimation was found, overestimation in five. A 15,000 multiplier gave slightly better results than 20,000. Average in 10 high-power fields was as good as 25. Abnormal counts could be assessed as well as normal. CONCLUSION: Average in 10 high-power field on a blood film microscopically and multiplying by 15,000 gives a platelet count reasonably close to automated machine counts in thousands per microliter.

Assessment of platelet numbers and morphology in the peripheral blood smear.

Automated systems are currently in widespread use for the assessment of patients' complete blood counts. The evaluation of the peripheral blood smear, however, still constitutes a pivotal tool in the evaluation of patients with hematologic disorders. This article focuses on disorders affecting the number or morphology of platelets as assessed by evaluation of a peripheral blood smear and also outlines some of their important clinical findings.