Comparison of acidified glycerol lysis test, Pink test and osmotic fragility test in hereditary spherocytosis: effect of incubation

In this study we compared the results of the acidified glycerol lysis test, the Pink test and the osmotic fragility test in 38 patients with hereditary spherocytosis and in healthy controls. The sensitivity of the acidified glycerol lysis test was 81.6% when performed within 3 h after blood collection. After incubating for 24 h, the sensitivity increased to 100% whereas the specificity remained maximal. Similar incubation did not improve the diagnostic utility of the Pink test. All patients, but none of the controls, showed a positive osmotic fragility test. It is concluded, because of sensitivity and specificity in this study, that the acidified glycerol lysis test after incubation and the osmotic fragility test are superior to the Pink test in detecting spherocytosis.     

酸化甘油溶解试验在儿科临床的应用

本文报道20例遗传性球形细胞增多症(HS),15例溶血性贫血(溶贫)及45例正常初生～12岁小儿微量外周血酸化甘油溶解试验测定值(AGLT_(50)),20例HS AGLT_(50)均<100秒。14例溶贫及45例正常小儿AGLT_(50)均>290秒。与红细胞渗透脆性试验等其它有关实验室指标比较,AGLT对HS诊断具有一定特异性及敏感性。适合儿科临床应用,并适用于HS家系调查。     

Diagnostic utility of the pre-incubated acidified glycerol lysis test in haemolytic and non-haemolytic anaemias.

The usefulness of the pre-incubated acidified glycerol lysis test (AGLT), a laboratory test for spherocytosis, has been investigated in a selected hospital population of 348 patients with haemolytic and non-haemolytic anaemia. The AGLT was positive in 58 out of 59 patients with hereditary spherocytosis. In all 32 patients with other types of hereditary haemolytic anaemia the AGLT was normal or equivocal, but clearly different from spherocytosis. Adults with a positive AGLT, but without hereditary spherocytosis, had auto-immune haemolytic anaemia, myelodysplastic syndrome or were pregnant women. In newborn infants the AGLT was positive, in the first week of life, in those babies having hereditary spherocytosis or immune haemolysis due to blood group incompatibility; no positive AGLT results were seen if no haematological explanation for neonatal hyperbilirubinaemia could be found. At the optimal cut-off point the sensitivity of the AGLT for hereditary spherocytosis was 98.3% and the specificity 91.1%, under the most unfavourable conditions. The AGLT is a very useful and simple test for the diagnosis of hereditary spherocytosis.     

Evaluation of single-tube osmotic fragility as a screening test for thalassemia

A single-tube osmotic fragility test has been proposed for thalassemia screening with a range of different concentrations of saline having been employed. We have compared the sensitivity and specificity of 0.32%, 0.34%, and 0.36% buffered saline, and on the basis of our findings, recommend the use of 0.36% saline. This gave definitely positive or equivocal results in 81 of 85 patients with beta thalassemia trait and in 4 of 4 with alpha(0) thalassemia trait. There were 14% false positive results in hematologically normal patients and 81% of the samples from patients with various variant hemoglobins gave positive results. The sensitivity was 95% and specificity 86%. The single-tube osmotic fragility test is potentially useful in under-resourced laboratories although it cannot replace automated red cell indices using electronic counters.     

联合试验在地中海贫血诊断中的应用

目的 :探讨红细胞平均体积 (MCV)、红细胞脆性及血红蛋白 (Hb)电泳联合试验在地中海贫血 (简称地贫 )中的诊断价值。方法 :用日本SysmexKX 2 1自动血细胞分析仪、中山医科大学红细胞脆性一管定量法、美国Helena公司KEP型全自动电泳分析系统 ,分别对本实验室经分子生物学技术确诊的 14 8例地贫及 81例非地贫样品进行MCV、红细胞脆性及Hb电泳测定 ,并对结果作相关统计学分析。结果 :MCV、红细胞脆性、Hb电泳单项试验对地中海贫血诊断的灵敏度及特异度分别为 91.9%、81.1%、83.8%及 79%、91.4 %、90 .1%。MCV与Hb电泳、红细胞脆性与Hb电泳二项试验平行联合的灵敏度及特异度分别为 98.6 %、96 .6 %及 71.6 %、82 .7% ;系列联合的灵敏度及特异度分别为 77%、6 8.2 %及 97.5 %、98.8%。MCV、红细胞脆性、Hb电泳三项试验平行联合的灵敏度、特异度为 10 0 %、6 5 .4 % ;系列联合的灵敏度及特异度为 6 2 .8%、10 0 %。经u检验 ,平行联合试验的灵敏度与各单项试验灵敏度之间、系列联合试验的特异度与各单项试验特异度之间差异有统计学意义 (P <0 .0 5 )。结论 :在地贫的诊断试验中 ,MCV、红细胞脆性、Hb电泳平行联合试验可提高灵敏度 ,系列联合试验可提高特异度 ,联合试验较单项试验有一定的优越性     

Cryohemolysis test as a diagnostic tool for hereditary spherocytosis

&ensp;The cryohemolysis test has been proposed as a new method of identifying hereditary spherocytosis. The purpose of the present study was to analyze the sensitivity and specificity of this method in comparison to the measurement of osmotic fragility. The examination included 61 patients suffering from hereditary spherocytosis and 58 patients with other hemolytic and nonhemolytic anemias. Hereditary spherocytosis patients showed significantly higher cryohemolysis values (median 29.7%, range 12.3&ndash;50.2%) than both normal subjects (median 3%, range 0.5&ndash;27%) and all other anemic patients excepting those with immune hemolytic anemia (median 4%, range 0.5&ndash;10.1%). Analysis of immune hemolytic anemia revealed broadly scattered values ranging from 1.4% to 53.5% (median 8.6%). Taking 15% as the threshold value, the sensitivity and specificity of the cryohemolysis test for hereditary spherocytosis were 95% and 96%, respectively. It is concluded that the simple-to-perform cryohemolysis test is quite comparable to the estimation of red cell osmotic fragility and therefore very useful as a diagnostic measure of hereditary spherocytosis. Received: February 18, 1999 / Accepted: May 27, 1999     

A simplified screening for alpha-thalassemia 1 (SEA type) using a combination of a modified osmotic fragility test and a direct PCR on whole blood cell lysates

In order to provide a rapid method for identifying alpha-thalassemia 1 in a region with massive population and limited resources, we have tested a rapid screening strategy. Preliminary screening was done using a modified one tube osmotic fragility test (OF test) followed by RBC indices; Hb analysis and detection of alpha-thalassemia 1 with the Southeast Asian deletion (SEA type) were performed by PCR. One hundred and seventy-five adult Thai subjects were studied. Fifty-one of the 175 subjects (29.1%) were positive for a modified OF test. They all had significantly lower MCV and MCH but higher RDW-CV values as compared to the OF negative group. A successful identification of alpha-thalassemia 1 deletion using a direct PCR on cell lysates was demonstrated. Among the 51 OF-test-positive subjects, 7 were found to be alpha-thalassemia 1 carriers, 3 of whom were also carriers of Hb E. No alpha-thalassemia 1 was detected in the OF-test-negative group. A combination of a modified OF test and a direct PCR analysis on whole blood cell lysates would therefore provide an effective screening for alpha-thalassemia 1 in the regions where a program of prevention and control of the disease remains underserved.     

Serum hepcidin as a diagnostic test of iron deficiency in premenopausal female blood donors

Background

Currently used indicators of iron status have limitations. Hepcidin, a key regulator of iron metabolism, is reduced in iron deficiency. We sought to determine the properties of hepcidin as a diagnostic test of iron deficiency.

Design and Methods

Sera from female, non-anemic, whole blood donors were analyzed for hepcidin (enzyme-linked immunosorbent assay), ferritin, soluble transferrin receptor and C-reactive protein. Iron deficiency was defined as (i) serum ferritin less than 15 ng/mL or (ii) soluble transferrin receptor /log(ferritin) index greater than 3.2 if the C-reactive protein concentration was less than 10 mg/L, or greater than 2.2 if the C-reactive protein concentration was greater than 10 mg/L). Receiver operating characteristic curves were plotted to determine the overall utility and identify optimal cut-points of hepcidin as a test of iron deficiency.

Results

In 261 blood donors the prevalence of iron deficiency defined by ferritin concentration was 59/261 [22.6% (17.5, 27.7)], whereas defined by soluble transferrin receptor/log(ferritin) index it was 53/261 [20.4% (15.4, 25.2)]. The 95% reference range of hepcidin concentration in the iron-replete population was 8.2–199.7 ng/mL. The area under the receiver operating characteristic curve for hepcidin compared with ferritin concentration less than 15 ng/mL was 0.87 (0.82, 0.92), while that compared with the soluble transferrin receptor /log(ferritin) index was 0.89 (95% CI 0.84, 0.93). For a diagnosis of iron deficiency defined by the soluble transferrin receptor/log(ferritin) index, hepcidin less than 8 ng/mL had a sensitivity of 41.5% and a specificity of 97.6%, while hepcidin less than 18 ng/mL had a sensitivity of 79.2% and a specificity of 85.6%.

Conclusions

Serum hepcidin concentration may be a useful indicator of deficient iron stores. Further studies are required to evaluate the role of hepcidin in the diagnosis of iron deficiency in other groups of patients.     

Expression of adhesion molecules on T lymphocytes in young children and infants – a comparative study using whole blood lysis or density gradient separation

We investigated the use of two sample preparation techniques (whole blood lysis [WBL], and Ficoll‐Hypaque density separation [FDS]) for flow cytometric estimation of adhesion molecule (CD54, CD62L and CD11b) expression on T lymphocytes from children less than 2 years old, comparing the results with normal adult controls. Using WBL methods, young children had lower percentages of CD3⁺/CD54⁺ and CD3⁺/CD11b⁺ lymphocytes, but not of CD3⁺/CD62L⁺ lymphocytes than adult controls. FDS was associated with significantly higher percentages of CD3⁺/CD62L⁺ and CD3⁺/CD11b⁺ lymphocytes in young children and adults alike, while the percentages of CD3⁺/CD54⁺ cells from adults was not affected by FDS. The percent expression of CD54, CD62L, and CD11b on T cells from both children and adults were significantly higher following FDS, with a greater increase in CD11b expression on T cells from young children, reaching adult levels. The mean fluorescence intensity (MFI) of CD62L on T cells from young children, which was lower than that of adults using WBL preparation, was significantly higher following FDS, reaching adult levels. The higher levels of adhesion molecule expression associated with FDS did not result from T‐cell activation, as assessed by CD69, CD25, and HLA‐DR expression. Thus, adhesion molecule expression on T lymphocytes from young children is more sensitive to modification by isolation procedures than that on adult T cells. Caution should therefore be exercised in interpreting adhesion molecule expression data on T cells from children.     

Detection and identification of occult HBV in blood donors in Taiwan using a commercial,multiplex, multi‐dye nucleic acid amplification technology screening test

Platelet components became routinely available to many institutions in the late 1960s and since then utilization has steadily increased. Platelets are produced by three principal methods and their manufacturing process is regulated by multiple agencies. As the field of platelet transfusion has evolved, a broad array of strategies to improve platelet safety has developed. This review will explore the evolution of modern platelet component therapy, highlight the various risks associated with platelet transfusion and describe risk reduction strategies that have been implemented to improve platelet transfusion safety. In closing, the reader will be briefly introduced to select investigational platelet and platelet‐mimetic products that have the potential to enhance platelet transfusion safety in the near future.     

Prevalence of Chikungunya,Dengue and Zika viruses in blood donors: a systematic literature review and meta-analysis

BackgroundBlood transfusion centres should understand the epidemiology of emerging diseases that are transmissible through the transfusion of blood components. The risk of transmission of arboviruses through this route has become apparent in recent years. The aim of our study is to summarise the reported prevalence (viraemic rate, seroprevalence and/or antigen detection) of Chikungunya (CHIKV), Dengue (DENV) and Zika (ZIKV) viruses in blood donors according to screening test used and world region.Materials and methodsWe conducted a systematic literature review and meta-analysis having searched for information in the main bibliographic databases (MEDLINE, Embase, and Scopus). The prevalence for each of the viruses was calculated according to the screening test used and geographic location.ResultsWe included 18 records on CHIKV, 71 on DENV, and 27 on ZIKV. The highest prevalences of RNA for CHIKV were 1.9% in Puerto Rico (2014), 1.0% in Thailand (2009), and 1.0% in French Polynesia (2014–15). The highest prevalences of RNA for DENV were 5.5% in Saudi Arabia (2015–16), 2.3% in Madeira, Portugal (2012–13), and 0.6% in Brazil (2012). The highest prevalences of RNA for ZIKV were 2.8% in French Polynesia (2013–14), 2.7% in Brazil (2015–16), and 1.8% in Martinique (2016). Overall seroprevalence, as assessed by IgG antibodies, was 21.6% for CHIKV, 24.0% for DENV, and 5.1% for ZIKV.DiscussionOur study shows a high proportion of donors who are viraemic and asymptomatic, especially during outbreaks, with prevalences surpassing 5% for DENV, 1% for CHIKV, and 2% for ZIKV. These data confirm a clear threat to blood transfusion safety. The elevated seroprevalence for these three arboviruses is also indicative of their wide circulation in populations, correlating with an increased risk of infected but asymptomatic donors. Health centres and institutions must address this threat, especially in tropical regions where the biggest outbreaks occur.     

A pair of naturally occurring antibodies may dampen complement-dependent phagocytosis of red cells with a positive antiglobulin test in healthy blood donors

Background and Objective  It is known that red blood cells (RBC) from healthy blood donors with a positive direct antiglobulin test (DAT) for IgG continue to circulate despite carrying elevated numbers of IgG molecules. To unravel the properties of these RBC-bound IgG, we studied them not only on whole RBC populations, but also on density-fractionated RBCs.
Materials and Methods  The properties of acid-eluted RBC-bound IgG and plasma IgG were studied by ELISA for binding to RBC proteins and opsonins, and by blotting. In vitro phagocytosis was studied on density-separated RBCs.
Results  IgG-DAT-positive blood donors carried most IgG molecules on dense RBCs and had more RBCs of high density than DAT-negative controls. Their densest RBCs were older than the oldest RBCs of DAT-negative controls, based on the band 4·1a/b ratio. In vitro phagocytosis of senescent RBCs from IgG-DAT-positive donors was 1·5 to 2 fold higher than that of senescent control cells, but the same or less in the presence of physiological IgG concentrations, implying that RBC-bound IgGs impaired complement-dependent uptake. The IgG molecules on these DAT-positive RBCs comprised anti-band 3 naturally occurring antibodies (NAbs) and were two- to fivefold enriched in anti-C3 and framework-specific anti-idiotypic NAbs as compared to controls. Correspondingly, anti-C3 and framework-specific anti-idiotypic NAbs were proportionally elevated in the plasma of two-thirds of DAT+ donors.
Conclusions  Extra-binding of anti-C3 together with anti-idiotypic NAbs to senescent RBC-associated C3 fragments may suppress complement-dependent RBC phagocytosis and may prolong the in vivo life span of RBCs.     

Safety and feasibility of symptom-limited cardiopulmonary exercise test using the modified Naughton protocol in children with cerebral palsy: An observational study

Variables derived from the cardiopulmonary exercise test (CPX) provide objective information regarding the exercise capacity of children with cerebral palsy (CP), which can be used as the basis for exercise recommendations. Performing maximal CPX might not be appropriate, safe, or practical for children with CP. In the present study, the safety and feasibility of symptom-limited CPX using the modified Naughton protocol, a submaximal protocol, were investigated in children with CP, Gross Motor Function Classification System (GMFCS) level I or II. The present study included 40 children aged 6 to 12 years with CP who underwent symptom-limited CPX. CPX was performed to measure cardiopulmonary fitness using a treadmill with a modified Naughton protocol. Motor capacity was assessed using the Gross Motor Function Measure (GMFM), Pediatric Balance Scale (PBS), Timed Up and Go (TUG) test, and 6-minute walk test. Thirty-seven children with CP successfully completed testing without any adverse events during or immediately after CPX (dropout rate 7.5%). The reason for test termination was dyspnea (51.4%) or leg fatigue (48.6%). Based on the respiratory exchange ratio (RER), 21 of 37 (56.8%) children chose premature termination. The relationship between the reason for test termination and RER was not statistically significant (Spearman rho = 0.082, P = .631). CPX exercise time was strongly correlated with GMFM (Spearman rho = 0.714) and moderate correlation with PBS (Spearman rho = 0.690) and TUG (Spearman rho = 0.537). Peak oxygen uptake during CPX showed a weak correlation with GMFM and a moderate correlation with PBS. This study revealed that symptom-limited CPX using the modified Naughton protocol was safe and feasible for children with CP and GMFCS level I or II.     

Seroprevalence of dengue in Trinidad using rapid test kits: a cord blood survey

A cross-sectional sero-epidemiological study was conducted to determine the prevalence of dengue in Trinidad. Two commercial rapid test kits, PanBio Dengue Duo IgM and IgG Rapid Strip Test and the Bio-Check Plus Dengue G/M Cassette Test (Brittney) were used. The immunosorbent assay (ELISA) (FOCUS Technologies, California) was used as the control. One hundred and twenty five cord blood samples were collected (46 from Mt. Hope Women's Hospital (MH) and 79 from the San Fernando General Hospital (SF)). All blood samples were tested in accordance with the two rapid kits and ELISA assay manufacturer's instructions. From 125 cord blood samples, the IgG FOCUS ELISA results showed 93.5 and 95% infections at MH and SF, respectively. Whereas the Brittney and PanBio kits showed 10.9 and 5.1%, and 26.1 and 50.6% for MH and SF, respectively. Based on the FOCUS ELISA (control) assays, the combined seroprevalence rate from north and south Trinidad was 94.4%. IgG and IgM sensitivity and specificity levels were higher in the PanBio than Brittney test kits. The high seroprevalence rates observed in Trinidad are discussed to stimulate more research to explain this phenomenon and to prevent the Southeast Asian scenario from developing in the Americas.     

Measuring gastric emptying of semisolids in children using the C-acetate breath test: a validation study

Background and aim. Radioscintigraphy is the gold standard for evaluation of gastric emptying in children, but requires exposure to ionising radiation. Therefore, the aim of the study was to validate the non-radioactive ¹³C-acetate breath test in children in comparison to radioscintigraphy as reference method.Patients. Twenty-nine children with dyspeptic or respiratory symptoms were tested for gastric emptying disorders simultaneously performing the ¹³C-acetate breath test and radioscintigraphy.Methods. A semisolid oatmeal was doubly labelled with 150 mg ¹³C-acetate and 50 MBq ^99mTechnetium. Breath samples were collected every 5–10 min for 4 h. After mass spectrometrical ¹³C-analysis, curve fitting of the ¹³C-cumulative recovery to the modified power exponential function Y=m(1−e^−kt)^β calculated the half emptying times of the breath test (t_1/2^breath). Scintigraphic image acquisition began immediately after the ingestion of the ^99mTechnetium-labelled testmeal at a rate of one frame every 60 s for 1 h.Results. Six children showed delayed gastric emptying in scintigraphy (t_1/2^scinti>60 min). All these children had prolonged half emptying times t_1/2^breath in the ¹³C-acetate breath test. Using a cut-off t_1/2^breath>90 min, the ¹³C-acetate breath test had a sensitivity of 100% and a specificity of 85%. Scintigraphic and breath test half emptying times were linearly correlated (Y=0.80x+47.68, r=0.76, P<0.00001).Conclusions. The ¹³C-acetate breath test proves to be a reliable, non-radioactive alternative for measuring gastric emptying in children.     

Use of fecal occult blood test in hospitalized patients: Survey of physicians practicing in a large central Canadian health region and Canadian gastroenterologists

BACKGROUND:

Although the fecal occult blood test (FOBT) was developed for colorectal cancer screening in the outpatient setting, it continues to be used among hospitalized patients. No previous study has evaluated the knowledge, beliefs and attitudes of practicing physicians on the use of FOBT among hospitalized patients and compared practices among physicians with different medical specialty training.

OBJECTIVE:

To survey physicians in the Winnipeg Regional Health Authority (WRHA) and Canadian gastroenterologists (GIs) on the use of FOBT in hospitals.

METHODS:

A survey was distributed by e-mail to internists (n=198), emergency medicine (EM) physicians (n=118), general surgeons (n=47) and family medicine (FM) physicians with admitting privileges (n=29) in the WRHA. Canadian GIs were surveyed through the membership database of the Canadian Association of Gastroenterology (CAG) (n=449). The survey included items regarding demographics of the respondents and their current use of FOBT in hospitals.

RESULTS:

Response rates ranged from 18% among CAG members to 69% among FM physicians in the WRHA. General internal medicine, general surgeon and GI respondents were less likely to order a FOBT and less likely to believe that an FOBT was useful in assessing emergency room or hospitalized patients when compared with FM and EM respondents (P<0.001). The most common indications for ordering a FOBT were black stools and anemia with and without iron deficiency. Two-thirds of EM physicians preferred point-of-care testing rather than laboratory reporting of FOBT.

CONCLUSIONS:

The present survey suggests that FOBTs are commonly used in hospitals by EM and FM physicians for indications such as anemia and black stools.     

Prevalence and trend of HIV infection among voluntary blood donors in China since implementation of the Blood Donation Law: a systematic review and meta‐analysis

Objective  In 1998, the Blood Donation Law was enacted in China in response to the outbreak of HIV endemic in central rural China as a result of unhygienic and commercial blood collection. This study aims to provide a first comprehensive review of available data on the prevalence, trend and other epidemiological characteristics of HIV infection among voluntary blood donors since 1998. Methods  Major English and Chinese databases were searched and a systematic review was constructed. Pooled infection rates by province and year were calculated using random‐effect or fixed‐effect models. Results  A total of 87 studies met our inclusion criteria. A total of 2573 HIV‐positive cases were identified among voluntary blood donors in the past 10 years; the pooled prevalence was 13.22/100 000, with a range of 0.74–125.97 per 100 000. Among the 24 provinces that reported yearly data, the prevalence of HIV increased from 5.62/100 000 to 28.90/100 000. The male‐to‐female ratio was 2.8; about 60% were below the age of 30 years. Conclusions  The prevalence of HIV in voluntary blood donors has risen steadily and fast. Efficient measures need to be taken urgently to prevent HIV test‐seeking through blood donor programmes, to promote voluntary blood donation in low‐risk groups and to enforce the Blood Donation Law strictly.