A Comparison Study: Possible Bias in Troponin I Measurement Obtained with a Point of Care Testing and a Central Laboratory Analyzers Employing Different Biological Matrices and Anticoagulants.

BACKGROUND: high-sensitive cardiac TroponinI (hs-cTnI) is widely used for diagnosis of acute coronary syndromes. The latest recommendation for hs-cTnI determination is the protocol 0-1 h finalized to improve the rule out accuracy of the test. A Point of Care Testing able to guarantee these performances could be very useful due to reducing the turnaround time and ruling out patients suspected of ACS, especially by using biological matrices that are not required for centrifuge. The aim of our work is to compare the results for hs-cTnI obtained using different biological matrices and anticoagulants, obtained between Atellica® VTLi hs-cTnI POCT and Access AccuTnI+3 DxI800 performances, in order to establish a possible bias derived directly from these pre-analytical conditions. METHODS: Li-heparinized pool samples were primary employ for hs-cTnI with Atellica® VTLi as whole blood, then centrifuged and tested on Atellica® VTLi and DxI800. K3EDTA pool samples were centrifuged and measured on DxI800 too. A comparison of methods was performed according to CLSI_EP-09A2 protocol. Constant and proportional errors were investigated with Deming regression. Bias between methods was evaluated with the Bland Altman test. RESULTS: comparing whole blood lithium heparin results obtained with Atellica versus lithium heparin and K3EDTA plasma tested on DxI 800, the Deming regression revealed a proportional error, whereas in both cases Bland Altman highlighted a minimal underestimation. A similar performance was revealed when considering plasma lithium heparin tested on Atellica versus lithium heparin and K3EDTA plasma obtained with DxI800, confirming the same underestimation. Considering values close to the cut off, no significant differences were found. CONCLUSIONS: in the laboratory, the estimation of the bias of two different analyzers is pivotal. Once more this is crucial when different biological matrices and anticoagulants are employed for the analysis. Our study demonstrates that no significant differences among the two matrices are present when comparing Atellica and DxI800 performances.

Use of the reticulocyte channel warmed to 41 °C of the XN-9000 analyzer in samples with the presence of cold agglutinins

ABSTRACT Objectives The purpose of this study was to compare data obtained from the reticulocyte channel (RET channel) heated to 41 °C with those obtained from impedance channel (I-Channel) at room temperature in the samples with the mean corpuscular hemoglobin concentration (MCHC) < 370 g/L and in samples with the MCHC > 370 g/L, in the presence of cold agglutinins. Methods In this study, 60 blood samples (group 1) with the MCHC < 370 g/L (without cold agglutinins) and 78 blood samples (group 2) with the MCHC > 370 g/L (with cold agglutinins) were used to compare the two analytical channels of the XN-9000 analyzer in different preanalytical conditions. The parameters evaluated in both groups were the following: red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), mean cell volume (MCV), RBC-most frequent volume (R-MFV), mean hemoglobin concentration (MCH) and mean cellular hemoglobin concentration (MCHC). Results The results of this study showed an excellent correlation with both channels of the XN-9000 analyzer in samples with and without cold agglutinins, except for the MCHC. The bias between the values obtained in the I-channel and those obtained in the RET channel of both groups was insignificant and remained within the limits of acceptability, as reported by Ricos et al. for all considered parameters, except for MCHC. Conclusions The presence of cold agglutinins in blood samples can be detected by a spurious lowering of the RBC count and by a spurious increase in the MCHC. The RET channel represents a great opportunity to correct the RBC count in a rapid manner without preheating. However, neither methodology can completely solve the residual presence of cold agglutinins in all samples, despite the MCHC values being < 370 g/L.

Impact of the preparation method of red cell concentrates on transfusion indices in thalassemia patients: A randomized crossover clinical trial.

BACKGROUND: The average hemoglobin content of red cell concentrates (RCC) varies depending on the method of preparation. Surprisingly less data are available concerning the clinical impact of those differences. STUDY DESIGN AND METHODS: The effects of two types of RCC (RCC-A, RCC-B) on transfusion regime were compared in a non-blinded, prospective, randomized, two-period, and crossover clinical trial. RCC-A was obtained by whole blood leukoreduction and subsequent plasma removal, RCC-B removing plasma and buffy coat first, followed by leukoreduction. Eligible patients were adult, with transfusion-dependent thalassemia (TDT). RESULTS: RCC-A contained 63.9 (60.3-67.8) grams of hemoglobin per unit (median with 1st and 3rd quartile), RCC-B 54.5 (51.0-58.2) g/unit. Fifty-one patients completed the study. With RCC-B, the average pre-transfusion hemoglobin concentration was 9.3 ± 0.5 g/dl (mean ± SD), the average transfusion interval 14.2 (13.7-16.3) days, the number of RCC units transfused per year 39.3 (35.4-47.3), and the transfusion power index (a composite index) 258 ± 49. With RCC-A, the average pre-transfusion hemoglobin concentration was 9.6 ± 0.5 g/dl (+2.7%, effect size 0.792), the average transfusion interval 14.8 (14.0-18.5) days (+4.1%, effect size 0.800), the number of RCC units transfused per year 34.8 (32.1-42.5) (-11.4%, effect size -1.609), and the transfusion power index 272 ± 61 (+14.1%, effect size 0.997). All differences were statistically highly significant (p < .00001). The frequency of transfusion reactions was 0.59% with RCC-A and 0.56% with RCC-B (p = 1.000). CONCLUSION: To reduce the number of RCC units consumed per year and the number of transfusion episodes, TDT patients should receive RCC with the highest average hemoglobin content.

Donation after circulatory death and liver transplantation: a cohort study.

Donations after circulatory death (DCD) are still challenging in Italy because of prolonged ischemia time (tWIT) due to the law and logistical issues. This cohort study was primarily aimed at assessing the association between successful transplantation and DCD types in the North Italy Transplant program. Adjusted risk ratios (RR) and 95% confidence intervals (CIs) for type III versus type II DCD were estimated using a Poisson regression model with a robust error variance. All consecutive DCD between 2008 and 2020 were included. Among 142 DCD, 102 were eligible for liver donation, and 96 were proposed: 68/69 (99%) and 28/33 (85%) type III and II DCD, respectively. Sixty-nine livers were recovered, 51/68 (75%) from type III and 18/28 (64%) from type II DCD, respectively (RR: 1.18; 95% CI: 0.87-1.60). After ex-vivo perfusion, 50/68 (74%) and 14/28 (50%) livers from type III and type II DCD were transplanted (RR: 1.49; 95% CI: 1.01-2.19). The estimate decreased after further controlling for tWIT (RR: 1.11; 95% CI: 0.55-2.24). Five patients (7.8%) experienced a PNF, 3/50 and 2/14 from type III and type II DCD, respectively. Type III DCD livers were more likely to be transplanted than type II. Warm ischemia time might explain this difference.

Use of the reticulocyte channel warmed to 41°C of the XN-9000 analyzer in samples with the presence of cold agglutinins.

OBJECTIVES: The purpose of this study was to compare data obtained from the reticulocyte channel (RET channel) heated to 41°C with those obtained from impedance channel (I-Channel) at room temperature in the samples with the mean corpuscular hemoglobin concentration (MCHC)<370g/L and in samples with the MCHC>370g/L, in the presence of cold agglutinins. METHODS: In this study, 60 blood samples (group 1) with the MCHC<370g/L (without cold agglutinins) and 78 blood samples (group 2) with the MCHC>370g/L (with cold agglutinins) were used to compare the two analytical channels of the XN-9000 analyzer in different preanalytical conditions. The parameters evaluated in both groups were the following: red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), mean cell volume (MCV), RBC-most frequent volume (R-MFV), mean hemoglobin concentration (MCH) and mean cellular hemoglobin concentration (MCHC). RESULTS: The results of this study showed an excellent correlation with both channels of the XN-9000 analyzer in samples with and without cold agglutinins, except for the MCHC. The bias between the values obtained in the I-channel and those obtained in the RET channel of both groups was insignificant and remained within the limits of acceptability, as reported by Ricos et al. for all considered parameters, except for MCHC. CONCLUSIONS: The presence of cold agglutinins in blood samples can be detected by a spurious lowering of the RBC count and by a spurious increase in the MCHC. The RET channel represents a great opportunity to correct the RBC count in a rapid manner without preheating. However, neither methodology can completely solve the residual presence of cold agglutinins in all samples, despite the MCHC values being < 370g/L.

Solid Organ Transplantation in the Coronavirus Disease 2019 Era: "The Great Bet" in the North Italy Transplant Program Area.

INTRODUCTION: Solid organ transplantation is challenging for waitlist patients during the coronavirus disease 2019 (COVID-19) pandemic. AIM: This study investigates COVID-19 incidence and mortality in patients transplanted in the North Italy Transplant program (NITp) during the outbreak. MATERIALS AND METHODS: All consecutive patients transplanted from February 20 to April 3, 2020 (6 weeks), were included in our cohort and were observed for at least 4 weeks. Survival analyses were performed. RESULTS: In this study, 124 patients were transplanted with 12 (9.7%) hearts, 4 (3.2%) lungs, 39 (31.4%) livers, 67 (54%) kidneys, and 2 (1.6%) combined kidney-pancreas. Recipients' mean age was 51 years (standard deviation [SD] ± 16.6), and 76 of 124 (61%) were men. Five (4%) patients developed COVID-19 after a mean of 13 days (SD ± 6.7), with a cumulative incidence of 4.0% (95% confidence interval [CI], 0.5-7.5). During the follow-up period, 5 of 124 (4%) recipients died; overall mortality was 4.3% (95% CI, 0.6-8.0), with only 1 patient dying of COVID-19, for a COVID-19-related mortality of 0.8% (95% CI, 0-6.0). CONCLUSIONS: This study showed a low COVID-19 incidence and COVID-19-related mortality in patients transplanted during the COVID-19 pandemic. Further studies with a longer follow-up period are mandatory to confirm the safety of transplant procedures.

A STARD-compliant prediction model for diagnosing thrombotic microangiopathies.

Aim of the study was the definition of a predictive model for the initial diagnosis of thrombotic microangiopathies (TMA). We retrospectively collected data on all adult patients admitted to the Gemelli Hospital from 2010 to 2014. ICD-9 codes from primary diagnoses were used for TMA diagnosis. Demographic and laboratory characteristics on admission of patients with TMA were then compared with a random sample of 500 patients with other diagnoses. The prediction model was externally validated in a cohort from another hospital. Overall, 23 of 187,183 patients admitted during the study period received a primary diagnosis of TMA. LDH (OR 1.26, 95% CI 1.05, 1.63) and platelets (OR 0.96, 95% CI 0.94, 0.98) were the only independent predictors of TMA. The AUROC of the final model including only LDH and platelets was 0.96 (95% CI 0.91, 1.00). The Hosmer-Lemeshow (HL) test (p = 0.54) suggested good calibration. Our model also confirmed good discriminatory power (AUROC 0.72 95% CI 0.60, 0.84) and calibration (HL test p = 0.52) in the validation sample. We present a simple prediction model for use in diagnosing TMA in hospitalized patients. The model performs well and can help clinicians to identify patients at high risk of TMA.

Mobile phone radiofrequency exposure has no effect on DNA double strand breaks (DSB) in human lymphocytes.

BACKGROUND: The use of mobile phones has been associated with an increased risk of developing certain type of cancer, especially in long term users. Therefore, this study was aimed to investigate the potential genotoxic effect of mobile phone radiofrequency exposure on human peripheral blood mononuclear cells in vitro. METHODS: The study population consisted in 14 healthy volunteers. After collection of two whole blood samples, the former was placed in a plastic rack, 1 cm from the chassis of a commercial mobile phone (900 MHz carrier frequency), which was activated by a 30-min call. The second blood sample was instead maintained far from mobile phones or other RF sources. The influence of mobile phone RF on DNA integrity was assessed by analyzing γ-H2AX foci in lymphocytes using immunofluorescence staining kit on AKLIDES. RESULTS: No measure of γ-H2AX foci was significantly influenced by mobile phone RF exposure, nor mobile phone exposure was associated with significant risk of genetic damages in vitro (odds ratio comprised between 0.27 and 1.00). CONCLUSIONS: The results of this experimental study demonstrate that exposure of human lymphocytes to a conventional 900 MHz RF emitted by a commercial mobile phone for 30 min does not significantly impact DNA integrity.

Red blood cell distribution width in patients with limb, chest and head trauma.

INTRODUCTION: This study investigated the values of red blood cell distribution width (RDW), an emerging and independent predictor of morbidity and mortality, in patients with limb, chest and head trauma. MATERIAL AND METHODS: The study sample consisted of all patients who attended the emergency department (ED) of the University Hospital of Parma for limb, chest and head traumas requiring admission to hospital wards during the year 2014. The controls consisted of outpatients living in the same geographical area and undergoing routine laboratory testing for health check-up. RESULTS: The final study sample consisted of 290 patients with limb (n = 97), chest (n = 49) or head (n = 144) trauma and 967 outpatients. Significantly increased RDW values at admission were observed in all trauma patients compared with controls. Although the frequency of increased RDW (> 14.6%) was higher in all trauma patients than in controls, a subanalysis revealed that increased RDW values were significantly more frequent in patients with head trauma than in controls, but not in those with limb or chest trauma. In multivariate analysis, a significant association was found between head trauma and hemoglobin (p < 0.001) or RDW (p = 0.005). Head trauma patients had a ~3-fold higher likelihood of increased RDW values than controls. The negative and positive predictive values of increased RDW for predicting the presence of head trauma were 0.90 (95% CI: 0.88-0.92) and 0.24 (95% CI: 0.19-0.30). CONCLUSIONS: The results of this study highlight that RDW is increased in patients admitted to the ED with head trauma.

The serum concentrations of leptin and MCP-1 independently predict low back pain duration.

BACKGROUND: Low back pain (LBP) is a very frequent condition, affecting most people at some point throughout their life. This cross-sectional study was aimed to investigate a selected panel of cytokines and inflammatory biomarkers in patients with or without LBP. METHODS: The study population consisted of 104 patients diagnosed with LBP (52 non-persistent and 52 persistent) and 52 healthy subjects with no LBP. Blood samples were collected for assessment of adiponectin, leptin, monocyte chemoattractant protein-1 (MCP-1) and C reactive protein (CRP). The duration of LBP was categorized as "no pain", "non-persistent LBP" and "persistent LBP". RESULTS: Higher values of CRP and lower concentrations of both leptin and MCP-1 were found in LBP patients compared to controls, whereas adiponectin did not differ among groups. MCP-1 was also lower in patients with non-persistent than in those with persistent LBP. Age, leptin (relative risk, 11.8; 95% CI, 3.9-35.8) and MCP-1 (relative risk, 2.7; 95% CI, 1.7-4.4) were independently associated with presence and duration of LBP. The combination of age, leptin and MCP-1 predicted 61% of the risk of LBP duration. The area under the curve of MCP-1 for distinguishing persistent from non-persistent LBP was 0.65 (95% CI, 0.54-0.76). CONCLUSIONS: Then results of our study suggest that leptin and MCP-1 may be promising biomarkers for diagnosis of acute LBP and its risk to become chronic.

DNA injury is acutely enhanced in response to increasing bulks of aerobic physical exercise.

The aim of this study was to evaluate DNA damage in response to increasing bulks of aerobic physical exercise. Fifteen adult and trained athletes performed four sequential trials with increasing running distance (5-, 10-, 21- and 42-km) in different periods of the year. The γ-H2AX foci parameters were analyzed before and 3h after the end of each trial. The values of all γ-H2AX foci parameters were enhanced after the end of each trial, with values gradually increasing from the 5- to the 42-km trial. Interestingly, a minor increase of γ-H2AX foci was still evident after 5- to 10-km running, but a much higher increase occurred when the running distance exceeded 21km. The generation of DNA injury was then magnified by running up to 42-km. The increase of each γ-H2AX foci parameter was then found to be associated with both running distance and average intensity. In multivariate linear regression analysis, the running distance was significantly associated with average intensity and post-run variation in the percentage of cells with γ-H2AX foci. We can hence conclude that aerobic exercise may generate an acute DNA damage in trained athletes, which is highly dependent upon running distance and average intensity.

Red blood cell distribution width and haemoglobin are associated with hospital admission in patients with acute allergic reactions.

INTRODUCTION: Red blood cell distribution width (RDW) is significantly associated with a variety of human disorders. This study aimed to investigate whether RDW value at admission may predict the need of hospitalisation in patients presenting to the emergency department (ED) with acute allergic reactions. MATERIALS AND METHODS: The study population consisted of adult patients (aged > 17) admitted to the ED for acute allergic reactions. RESULTS: One hundred and thirty-two subjects were included, 12 of whom (9%) required hospital admission for severity of symptoms. Patients who needed hospital admission displayed significantly lower values of haemoglobin and significantly higher values of RDW-coefficient of variation (RDW-CV). In multivariate analysis, haemoglobin and RDW-CV were found to be independent predictors of hospital admission. The area under the curve (AUC), sensitivity and specificity for predicting hospital admission were 0.72, 0.88 and 0.42 for haemoglobin and 0.73, 0.88 and 0.50 for RDW-CV, respectively. The combination of these tests (both positive) was characterised by 0.76 AUC, 0.83 sensitivity, 0.67 specificity, 0.96 negative predictive value and 0.30 positive predictive. DISCUSSION: The results of this study suggest that two common and inexpensive parameters such as haemoglobin and RDW are independent predictors of hospital admission in patients presenting to the ED with acute allergic reactions.

The Mean Platelet Volume Is Decreased in Patients Diagnosed with Venous Thromboembolism in the Emergency Department.

Platelets are small corpuscular elements, which play an essential role in hemostasis and thrombosis. As active players in the thrombotic process, hyperactive platelets are involved in the pathogenesis of cardiovascular disorders. Nevertheless, the role of platelet size, as a biological marker of platelet activation, remains debated in the setting of venous thrombosis. Therefore, we conducted a retrospective case-control study to clarify the potential association between mean platelet volume (MPV) and newly diagnosed venous thromboembolism (VTE) by reviewing data of all consecutive patients receiving a diagnosis of VTE at the emergency department (ED) of the University Hospital of Parma (Italy) between January and December, 2014. The control population was represented by outpatients undergoing routine laboratory testing for health checkup at the phlebotomy center of the same University Hospital during the same period. MPV was found to be comparatively decreased in the entire cohort of patients with VTE compared with the outpatient population, as well as in those with isolated deep vein thrombosis (DVT) or pulmonary embolism (PE). A decreased MPV value (i.e., < 10.8 fL) was found to be associated with an increased risk of diagnosing VTE (relative risk, 1.18; 95% CI, 1.09-1.28; p < 0.001), as well as of diagnosing isolated DVT (relative risk, 1.19; 95% CI, 1.07-1.31; p = 0.001) and isolated PE (relative risk, 1.17; 95% CI, 1.04-1.30; p = 0.007). A decreased MPV value in active cancer patients was associated with the highest risk of diagnosing thrombosis (relative risk, 1.29; 95% CI, 1.10-1.51; p = 0.002). These results support an inverse association between MPV and the risk of venous thrombosis at diagnosis.

Analytical Evaluation of Free Testosterone and Cortisol Immunoassays in Saliva as a Reliable Alternative to Serum in Sports Medicine.

BACKGROUND: This study was aimed to investigate whether measurement of free testosterone and cortisol in saliva is a reliable alternative to their assessment in serum for monitoring physical fitness in professional athletes. METHODS: We studied 25 members of the soccer team Parma F.C., playing in Italian major football league. Blood and saliva samples were collected at fasting, before a regular training session. Cortisol, total and free testosterone, as well as the ratio between free testosterone and cortisol, were assessed in paired serum and saliva samples, and their results were compared. RESULTS: An excellent correlation was found between serum and saliva cortisol (r = 0.751; P < 0.001). A significant correlation was also observed between free testosterone in serum and saliva (r = 0.590; P = 0.002), whereas no significant correlation was found between total testosterone in serum and saliva (r = 0.181; P = 0.387). A significant correlation was found for the free testosterone to cortisol ratio in serum and saliva (r = 0.43; P = 0.031). All athletes (25/25; 100%) declared that they would feel more comfortable to have saliva rather than blood serially collected. CONCLUSIONS: The results of this study suggest that measurement of free testosterone and cortisol in saliva may be seen as a reliable alternative to their assessment in serum.

Value of Red Blood Cell Distribution Width on Emergency Department Admission in Patients With Venous Thrombosis.

Red blood cell distribution width (RDW) was found to be a useful parameter in a variety of cardiovascular and thrombotic disorders. Therefore, we conducted a retrospective case-control study to establish whether an association exists between RDW and venous thrombosis. The study population consisted of 431 consecutive patients who received a diagnosis of venous thrombosis in the emergency department (ED), thus including cases of superficial venous thrombosis, deep vein thrombosis (DVT), and/or pulmonary embolism (PE). The control population consisted of 967 matched outpatients who underwent routine laboratory testing. The RDW values were found to be significantly increased in patients with venous thrombosis compared to controls, with an incremental trend of values from patients with superficial thrombosis, isolate DVT, to PE. Increased RDW values were an independent risk factor for isolate DVT and PE, displaying a relative risk that was greater in patients with provoked DVT and PE that in those with unprovoked thrombosis after multiple adjustment for age, gender, hemoglobin, and mean corpuscular volume. Interestingly, RDW also exhibited a significant diagnostic performance at ED admission, displaying an area under the curve of 0.65 (95% confidence interval [CI] 0.62 to 0.68; p <0.001) for all cases of venous thrombosis, 0.63 (95% CI 0.59 to 0.68; p <0.001) for isolate DVT, and 0.70 (95% CI 0.65 to 0.75; p <0.001) for PE. The results of this study suggest that increased RDW not only is associated with venous thrombosis but may also increase the efficiency of baseline risk assessment of patients with suspected venous thrombosis on ED admission.

Blood Sampling Seasonality as an Important Preanalytical Factor for Assessment of Vitamin D Status.

BACKGROUND: The measurement of vitamin D is now commonplace for preventing osteoporosis and restoring an appropriate concentration that would be effective to counteract the occurrence of other human disorders. The aim of this study was to establish whether blood sampling seasonality may influence total vitamin D concentration in a general population of Italian unselected outpatients. METHODS: We performed a retrospective search in the laboratory information system of the University Hospital of Parma (Italy, temperate climate), to identify the values of total serum vitamin D (25-hydroxyvitamin D) measured in outpatients aged 18 years and older, who were referred for routine health check-up during the entire year 2014. RESULTS: The study population consisted in 11,150 outpatients (median age 62 years; 8592 women and 2558 men). The concentration of vitamin D was consistently lower in samples collected in Winter than in the other three seasons. The frequency of subjects with vitamin D deficiency was approximately double in samples drawn in Winter and Spring than in Summer and Autumn. In the multivariate analysis, the concentration of total vitamin D was found to be independently associated with sex and season of blood testing, but not with the age of the patients. CONCLUSIONS: According to these findings, blood sampling seasonality should be regarded as an important preanalytical factor in vitamin D assessment. It is also reasonable to suggest that the amount of total vitamin D synthesized during the summer should be high enough to maintain the levels > 50 nmol/L throughout the remaining part of the year.

Cardiac Troponin I is Increased in Patients with Polytrauma and Chest or Head Trauma. Results of A Retrospective Case-Control Study.

BACKGROUND: We performed a retrospective case-control study to assess the values of cardiac troponin I (cTnI) in a large number of patients admitted to the emergency department (ED) with different types of trauma. METHODS: The study population consisted of all patients aged 18 years or older admitted to the local ED with all types of traumas over a 1-year period. Results of cTnI were compared with those of 125 consecutive blood donors and 25 non-cardiac chest pain ED patients. RESULTS: The final study population consisted of 380 trauma patients, 10 with isolated abdominal trauma, 99 with isolated trauma of the limbs, 49 with isolated chest trauma, 145 with isolated head trauma and 77 with polytrauma. The concentration of cTnI did not differ among the three study populations, but the frequency of measurable values was substantially higher in patients with trauma (63%) than in blood donors and non-cardiac chest pain ED patients (both 20%). The frequency of cTnI values above the 99th percentile of the reference range was significantly higher in trauma patients (20%) than in blood donors (0%) and noncardiac chest pain ED patients (8%). Increased cTnI values were more frequent after head trauma (21%), chest trauma (27%) and polytrauma (29%) compared to patients with abdominal (0%) or limbs trauma (8%). CONCLUSIONS: These results suggest that the measurement of cardiac troponin may be advisable to identify potential cardiac involvement in trauma patients, especially in those with polytrauma and head or chest trauma.

Spring season birth is associated with higher emergency department admission for acute allergic reactions.

BACKGROUND: Acute allergic reactions are important causes of emergency department (ED) admission, imposing a significant clinical and organizational burden. Since the season of birth is linked with early exposure to allergens, this study was aimed to establish whether an association exists between season of birth and incidence and severity of acute allergic reactions in the ED. METHODS: The electronic hospital database was searched to identify all consecutive adult patients who were admitted to the ED for acute allergic reactions (acute urticaria, acute angioedema, urticaria-angioedema and anaphylaxis) during a 1-year period. RESULTS: The final study population consisted in 588 patients (328 women and 260 men; mean age 43 ± 18 years, range 16-96 years). Increased frequency of ED admission was observed for patients born in spring, whereas the lowest frequency was found for those born in autumn. Patients born in spring exhibited 1.19 and 1.12 higher risk of ED admission for acute allergic reactions compared to those born in autumn and in all other seasons, respectively. This difference remained significant in patients with allergic reaction attributable to drugs and in those with unknown triggers, whereas no pattern of seasonality was observed in patients with allergic reactions attributable to aliments, hymenoptera, chemicals or inhalants. Patients born in spring also exhibited 1.86 and 1.52 higher risk of being admitted to the ED for severe acute allergic reactions compared to those born in autumn and in all other seasons, respectively. CONCLUSIONS: Patients born in spring appear particularly vulnerable to allergic reactions requiring ED visit.

Analytical imprecision of lactate dehydrogenase in primary serum tubes.

BACKGROUND: Previous studies showed high frequency of duplicate errors of lactate dehydrogenase (LDH) measurement in primary lithium-heparin blood tubes. We hence evaluated imprecision of LDH testing and frequency of replicate errors in primary serum samples centrifuged at two different speeds. METHODS: Serum samples were collected from 15 healthy subjects and centrifuged at either 1300 g or 2000 g. Serum LDH was then measured on Beckman Coulter AU5800 using the International Federation of Clinical Chemistry-recommended procedure. Complete blood cell count of top layer of serum supernatant was also performed using Advia 2120. Imprecision was calculated as coefficient of variation of 10 replicates of each serum tube, whereas the frequency of replicate errors was compared to the desirable specifications for imprecision. RESULTS: Mean LDH values were slightly but significantly higher in serum samples centrifuged at 2000 g rather than 1300 g, whereas blood cell counts were similar. The mean imprecision of LDH was more than double in samples centrifuged at 2000 g than in those centrifuged at 1300 g (8% versus 3%). The percentage of replicate measurements exceeding the desirable specifications was more than threefold higher in samples centrifuged at 2000 g than in those centrifuged at 1300 g (30% versus 9%; P < .001). CONCLUSIONS: The lower frequency of replicated errors in LDH measurement observed using serum samples centrifuged according to manufacturer's instruction suggests that assay precision in serum is better if samples are centrifuged at 1300 g rather than 2000 g when the International Federation of Clinical Chemistry-recommended procedure is used.