HemoCue Hb-801 Provides More Accurate Hemoglobin Assessment in Blood Donors Than OrSense NBM-200.

Hemoglobin levels are commonly assessed to prevent causing or worsening of anemia in prospective blood donors. We compared head-to-head the accuracy of different technologies for measuring hemoglobin suitable for use in mobile donation units. We included 144 persons donating platelets at the Central Institute for Blood Transfusion and Immunology in Innsbruck, Austria. Hemoglobin levels were measured in venous blood using the portable hemoglobinometer HemoCue Hb-801 and noninvasively using OrSense NBM-200, and compared to values obtained with the Sysmex XN-430, an automated hematology analyzer employing the sodium lauryl sulphate method, which is broadly used as reference method in everyday clinical practice. Mean age of participants was 34.2 years (SD 13.0); 34.0% were female. Hemoglobin values measured with HemoCue were more strongly correlated with the Sysmex XN-430 (r = 0.90 [95% CI: 0.87-0.93]) than measured with OrSense (r = 0.49 [0.35-0.60]). On average, HemoCue overestimated hemoglobin by 0.40 g/dL (0.31-0.48) and OrSense by 0.75 g/dL (95% CI: 0.54-0.96). When using OrSense, we found evidence for higher overestimation at higher hemoglobin levels (proportional bias) specifically in females but not in males (Pdifference = .003). Sensitivity and specificity for classifying donors according to the hemoglobin donation thresholds were 99.2% (95% CI: 95.3%-100.0%) and 43.8% (23.1%-66.8%) for HemoCue vs 95.3% (89.9%-98.0%) and 12.5% (2.2%-37.3%) for OrSense. Areas under the receiver operating characteristic curves were higher using HemoCue vs OrSense both in females (0.933 vs 0.547; P = .044) and males (0.948 vs 0.628; P < .001). HemoCue Hb-801 measures hemoglobin more accurately than OrSense NBM-200 in the setting of mobile blood donation units. Our findings are particularly relevant for females, having in mind that anemia is more prevalent in females than in males.

Accuracy of detection of carboxyhemoglobin and methemoglobin in human and bovine blood with an inexpensive, pocket-size infrared scanner.

Detecting life-threatening common dyshemoglobins such as carboxyhemoglobin (COHb, resulting from carbon monoxide poisoning) or methemoglobin (MetHb, caused by exposure to nitrates) typically requires a laboratory CO-oximeter. Because of cost, these spectrophotometer-based instrument are often inaccessible in resource-poor settings. The aim of this study was to determine if an inexpensive pocket infrared spectrometer and smartphone (SCiO®Pocket Molecular Sensor, Consumer Physics Ltd., Israel) accurately detects COHb and MetHb in single drops of blood. COHb was created by adding carbon monoxide gas to syringes of heparinized blood human or cow blood. In separate syringes, MetHb was produced by addition of sodium nitrite solution. After incubation and mixing, fractional concentrations of COHb or MetHb were measured using a Radiometer ABL-90 Flex® CO-oximeter. Fifty microliters of the sample were then placed on a microscope slide, a cover slip applied and scanned with the SCiO spectrometer. The spectrograms were used to create simple linear models predicting [COHb] or [MetHb] based on spectrogram maxima, minima and isobestic wavelengths. Our model predicted clinically significant carbon monoxide poisoning (COHb ≥15%) with a sensitivity of 93% and specificity of 88% (regression r2 = 0.63, slope P<0.0001), with a mean bias of 0.11% and an RMS error of 21%. Methemoglobinemia severe enough to cause symptoms (>20% MetHb) was detected with a sensitivity of 100% and specificity of 71% (regression r2 = 0.92, slope P<0.001) mean bias 2.7% and RMS error 21%. Although not as precise as a laboratory CO-oximeter, an inexpensive pocket-sized infrared scanner/smartphone detects >15% COHb or >20% MetHb on a single drop of blood with enough accuracy to be useful as an initial clinical screening. The SCiO and similar relatively low cost spectrometers could be developed as inexpensive diagnostic tools for developing countries.

Capillary versus venous haemoglobin determination in the assessment of healthy blood donors.

BACKGROUND AND OBJECTIVES: To determine the accuracy of fingerstick haemoglobin assessment in blood donors, the performance of a portable haemoglobinometer (HemoCue Hb 201+) was prospectively compared with that of an automated haematology analyzer (Cell-Dyn 4000). Haemoglobin values obtained by the latter were used as the 'true' result. MATERIAL AND METHODS: Capillary fingerstick samples were assayed by HemoCue in 150 donors. Fingerstick samples from two sites, one on each hand, were obtained from a subset of 50 subjects. Concurrent venous samples were tested using both HemoCue and Cell-Dyn devices. RESULTS: Capillary haemoglobin values (HemoCue) were significantly greater than venous haemoglobin values (HemoCue), which in turn were significantly greater than venous haemoglobin values by Cell-Dyn (mean ± SD: 14.05 ± 1.51, 13.89 ± 1.31, 13.62 ± 1.23, respectively; P < 0.01 for all comparisons among groups). Nine donors (6%) passed haemoglobin screening criteria (≥ 12.5 g/dl) by capillary HemoCue, but were deferred by Cell-Dyn values (false-pass). Five donors (3%) were deferred by capillary sampling, but passed by Cell-Dyn (false-fail). Substantial variability in repeated fingerstick HemoCue results was seen (mean haemoglobin 13.72 vs. 13.70 g/dl, absolute mean difference between paired samples 0.76 g/dl). Hand dominance was not a factor. CONCLUSIONS: Capillary samples assessed via a portable device yielded higher haemoglobin values than venous samples assessed on an automated analyzer. False-pass and false-fail rates were low and acceptable in the donor screening setting, with 'true' values not differing by a clinically significant degree from threshold values used to assess acceptability for blood donation.

Evaluation of a portable hemoglobinometer (HemoCue) to control anemia in hepatitis C liver transplant recipients undergoing antiviral therapy.

BACKGROUND: Monitoring of anemia, the most frequent side-effect of antiviral therapy in hepatitis C virus (HCV)-infected liver transplant recipients, requires frequent blood tests and medical visits. AIMS: The primary aim of this study was to assess the usefulness and the accuracy of a portable hemoglobinometer (HemoCue) in patients receiving antiviral therapy after liver transplantation due to severe hepatitis C recurrence in the graft. The secondary aim was to evaluate the usefulness of this device in terms of cost-saving and time-saving benefits. METHODS: Multiple simultaneous hemoglobin measurements were obtained in venous blood by the reference method (ADVIA 120) and in capillary blood using HemoCue in 16 patients receiving antiviral therapy after liver transplantation. In addition, paired HemoCue measurements were taken to assess the reproducibility of this method, and correlation coefficients (CC) were calculated between them. Time requirements and cost of both procedures were recorded and compared. RESULTS: HemoCue showed an excellent reproducibility (CC 0.92) and very high correlation with the standard method (CC 0.89). Its accuracy in detecting anemia (hemoglobin ≤10 mg/dl) was excellent as well (area under the receiver operator characteristic curve, 0.96). The application of HemoCue in this cohort of patients resulted in a significant reduction in the economical expense and labor (i.e., time) per patient during follow-up. CONCLUSION: HemoCue is accurate and reproducible in measuring hemoglobin levels, and could be effectively used in this cohort of patients to control anemia during antiviral therapy. It could also help to reduce both overall costs and displacements, thereby improving the quality of life of these patients.

Different DCCT-aligned HbA1c methods and the GMS contract.

BACKGROUND: Previously, different analytical methods could be compared on statistical and clinical grounds. Since 2003, the UK Departments of Health and general practitioners agreed a new primary care contract. This contract utilises clinical targets resulting in a third way to compare analytical methods. METHODS: We compared two DCCT-aligned HbA1c analysers (Variant II analyser and a Tosoh G7) using 161 randomly selected patient specimens to see if different methods could lead to a difference in the classification for glycaemic control. RESULTS: Ninety-seven (60.2%) and 109 (67.7%) patient specimens had a HbA1c

Evaluation of the utility of the HemoCue 301 haemoglobinometer for blood donor screening.

BACKGROUND AND OBJECTIVES: Reliable blood donor screening requires more accurate measure of haemoglobin (Hb) than by either copper sulphate or the haemoglobin colour scale. The HemoCue haemoglobinometer has established a method for this, but it is considerably more expensive; a modified version (HemoCue 301) has now been developed with a cheaper reagent-free cuvette for use in budget-restricted situations. This report describes evaluation of the performance, the assessment of reproducibility and accuracy of this modified analyser against the reference technique for Hb measurement. MATERIALS AND METHODS: Over 300 routine blood samples from specimens received routinely in a hospital laboratory were tested in accordance with the International Committee for Standardization in Haematology (ICSH) protocol. Accuracy and linearity were confirmed by the reference method with the WHO international haemoglobincyanide reference standard. Tests were also performed on selected samples for checking interference by biochemical abnormalities and leucocytosis. The effects of various sample storage conditions prior to testing were also tested. RESULTS: Ninety per cent of results were within 4% of true values, 96% within 6% and in only three cases was the deviation > 10%, due to interference by bilirubinaemia and/or C-reactive protein. At an Hb value of 120 g/l for donor selection, there were no cases where the method would have been misleading. CONCLUSION: HemoCue 301 provides a simple and reliable anaemia screen method, conforming to the requirements of CLIA'88 regulations; it is reliable for discriminating Hb values for donor acceptance. The main advantage is that the cuvettes are significantly cheaper than the previous models, and will not deteriorate in adverse climatic conditions.

A noninvasive strategy for screening prospective blood donors for anemia.

BACKGROUND: The reliability of capillary hemoglobin (Hb) as an indicator for eligibility to donate blood is discussed controversially. Therefore, a noninvasive alternative with acceptable predictive values was established and evaluated. STUDY DESIGN AND METHODS: Donor candidates were selected according to their Hb level. The first donation was performed 6 weeks after this selection step. A venous blood sample was collected from all donors at the end of their donation and a postdonation Hb determination was performed. Donors with acceptable postdonation Hb values were permitted to donate next time without any predonation Hb measurement. Donors with low postdonation Hb values were permitted to donate only after a venous Hb measurement had shown an acceptable value. Sensitivity and specificity were determined by comparing the gold standard (i.e., venous Hb measurement) with the presented method of Hb estimation for 19,534 donors. RESULTS: Taking the postdonation Hb as an indicator for eligibility saved 97 percent of donors from being tested unnecessarily by capillary Hb measurement. This procedure resulted in a specificity of 92.6 percent and a sensitivity of 37.9 percent for Hb cutoff levels of 135 and 125 g per L for men and women, respectively. The sensitivity increased rapidly to 100 percent for Hb levels below 105 g per L. The average deviation from true Hb level was 6 g per L. CONCLUSION: The presented noninvasive method distinctly saves time and expenditure without endangering blood donors.

Precision, accuracy, and reliability of hemoglobin assessment with use of capillary blood.

BACKGROUND: Previous research has suggested that there may be significant within-subject variability, both site-to-site and over time, in hemoglobin concentrations in capillary blood. OBJECTIVE: This study examined the reliability of the portable hemoglobinometer (PHM) system with use of capillary blood and the implications of errors of the magnitude found for the classification of anemia status in individuals and population groups. The precision and accuracy of the method with use of venous blood were also tested. DESIGN: Three empirical data sets were used to measure reliability, precision, and accuracy of the PHM system [2 from Honduras (n = 87 and 141); 1 from Bangladesh (n = 73)]. Simulation data were used to assess the implications of errors for screening individuals for anemia and to estimate anemia prevalence. RESULTS: High within-subject variability (unreliability) was identified when capillary blood from the left hand was compared with that from the right hand (CV: 6.3%) and when measurements were taken on 4 consecutive days (CV: 7.0%). Reliability was only 69% and 50%, respectively. Precision and accuracy, however, were very high (concordance coefficients of 0.99 and 0.98 and CV < 1%). CONCLUSIONS: The simulation data showed that errors of the magnitude found due to unreliability can lead to misclassification of anemia status in individuals and small biases in anemia prevalence estimates. We recommend replicate sampling to reduce the influence of unreliability in the use of the PHM system with capillary blood.

Field evaluation of a novel haemoglobin measuring device designed for use in a rural setting.

OBJECTIVE: To evaluate the use of a robust, cheap method for haemoglobin estimation by non-laboratory-trained personnel in a rural setting. DESIGN: Comparative study. SETTING: Tintswalo Hospital, Acornhoek. PARTICIPANTS: 7 nursing sisters, 4 medical students, 2 lay persons. OUTCOME MEASURES: Haemoglobin estimates obtained with the colour scale were compared with the 'true Hb' values determined by the H x 3 Bayer-Technicon automated blood analyser. RESULTS: Although individuals varied in their abilities to use the colour scale, its performance was generally very good when measured against automated haemoglobinometry, as determined by bias and regression analysis and also in terms of its capacity to detect anaemia, as measured by sensitivity, specificity and positive and negative predictive values. CONCLUSIONS: Haemoglobin estimates obtained with the World Health Organisation colour scale are generally reliable, although cognisance should be taken of individual variability. While the utility of the device in monitoring response to therapy remains to be seen, it promises to be a suitable method for mass screening for anaemia.

Performance characteristics of Hemox-Analyzer for assessment of the hemoglobin dissociation curve.

The Hemox-Analyzer (TCS, Medical Products Division, Southampton, PA) is an automatic system for determining the oxyhemoglobin dissociation curve (ODC) and P50 values. The ODC is recorded during deoxygenation with nitrogen gas and plotted on graph paper; the oxygen tension is detected by a Clark electrode, while the oxyhemoglobin fraction (%HbO2) is evaluated by a dual-wavelength spectrophotometer. Even though this instrument has been commercially available for more than 20 years, its performance characteristics have been assessed. We evaluated the performance characteristics of the Hemox-Analyzer. P50 was tested in 28 healthy volunteers, in 16 anemic and in 9 polycythemic patients. To test its precision we evaluated both inter- and intra-assay variability. The system shows good precision: standard deviation was 0.39 for assays in duplicate, CV = 1.9% for intra-assay and CV = 3.0% for inter-assay measurements. The mean P50 values were 25.2 +/- 1.5 mmHg in normal volunteers and 27.3 +/- 1.4 mmHg in anemic patients. The Hemox-Analyzer is a simple, quick and reliable instrument for recording the oxyhemoglobin dissociation curve. Both the P50 value and observation of the fine structure of the curve can furnish information about the delivery of oxygen to tissues.

Improved strategy for screening prospective blood donors for anaemia.

Women (568) and men (531) attending blood donation sessions in Wessex in September, 1992, were assessed for anaemia by the standard CuSO4 method on finger-prick (FP) blood samples. The haemoglobin (Hb) concentration on FP samples and on venous blood was also checked using the HemoCue. Different FP samples from the same donors revealed a wide variation on HemoCue. We recommend retaining the CuSO4 method on FP samples as the initial screen, and follow-up of apparent failures by determining the Hb concentration on venous sampling with the HemoCue. As 54% of females were found on venous samples to be below the current recommended threshold (125 g/L) for Hb concentration, we also recommend lowering the threshold to 115 g/L for women, and to 130 g/L for men. We further recommend a close re-examination of normal haematology values for adults.

External quality assessment of the full blood count, and problems associated with the use of fixed blood preparations.

The experience of using a stored fixed blood preparation for external quality assessment of the full blood count is described. Differences between instruments employing differing technologies are highlighted and the problems of the control of the white cell differential count discussed.

Evaluación externa de calidad en hematología: hemoglobina (período 1989-1991) / External quality assessment in hematology: hemoglobin (1989-1991)

Se exponen los resultados obtenidos en el Programa de Evaluación Externa de Calidad (PEEC) en Hematología de la Federación Bioquímica de la provincia de Buenos Aires, durante el período 1989-1991. Este Programa está inserto en el Programa de Evaluación Externa de Calidad en Bioquímica Clínica. El mismo es de carácter voluntario, explícito o anónimo. Inicialmente fueron 911 los inscriptos, y en la actualidad han superado los 1300, incluyendo laboratorios de otras provincias. En esta etapa sólo se ha implementado la evaluación externa para la hemoglobinometría. Se llevaron a cabo ocho encuestas, una de ellas a dos niveles de concentración, observándose que los porcentajes de respuestas aceptados, es decir que caen dentro de Xñ3 DE, oscilan entre 31-95%, con coeficiente de variación (CV) entre 5.8-14.2%. Los porcentajes de laboratorios que se encuentran dentro del límite de aceptabilidad de ñ5% varían entre 22-51%. El envío simultáneo de muestras a dos niveles arrojó diferencias para ambos valores asignados de -10% y -13.5%, lo que indica presencia de un error sistemático. El grado de estandirización logrado está relacionado con el empleo mayoritario de espectrofotómetros de haz simple, del uso de un solo punto de calibración y, como factor más crítico aún, de la existencia de 7-8% de laboratorios que aún no han adoptado el método recomendado de cianmetahemaglobina, todo lo cual justifica ampliamente la continuidad del PEEC

[Evaluation of the Coulter STKS hematologic autoanalyzer]. / Valoración del autoanalizador hematológico Coulter STKS.

PURPOSE: To express the results of an evaluation of the Coulter STKS blood cell counter. MATERIAL AND METHODS: The following data were collected: inaccuracy, carry-over, linearity, comparison with other systems, suspect morphology alarms, stability of calibration, time-stability of samples and working velocity. The protocol recommended by the ICSH was followed for the first four of the above. RESULTS: Good results were achieved for cell counts and derived parameters. The leucocyte differential count showed fair results for neutrophils, lymphocytes, monocytes and eosinophils; false basophilia was usually associated with the presence of abnormal lymphocytes. No differences were found between adult and paediatric samples. The usefulness of the suspect morphology alarms was also evaluated; they were found fairly sensitive for the presence of stabs, large amounts of atypical lymphocytes and blast cells, and moderately sensitive for erythroblasts and platelet clumps. The predictive value of alarms was found high in any type of pathology, but scarcely valuable when considering the pathology indicated by the alarm, such predictive value being noticeably increased upon associated alarms. CONCLUSION: The Coulter STKS cell counter appears as adequate for the haematology laboratory running daily high number of samples with high pathologic rates.

An assessment of the operating characteristics of Coulter Counter Model S-Plus STKR.

BACKGROUND AND METHODS: The operating performance of the Coulter Counter S Plus STKR was evaluated in two hospital laboratories in Rome and in Florence. Experimental design conformed to both the ICSH and NCCLS Standards for the evaluation of hematologic analyzers, and to the ECCLS guidelines for the multicenter evaluation of analyzers in clinical chemistry. RESULTS AND CONCLUSIONS: Cell counts in K3 EDTA were unchanged over 6 hours at room temperature and 72 hours at 4 degrees C, while MCV, MPV and leukocyte differentials were far less stable. Carry over, precision and linearity met the manufacturer's specifications, while a satisfactory relative accuracy was demonstrated by determining reference values on an adult reference group and by comparing the instrument with the previous model S Plus IV D. The accuracy of the leukocyte differentials was evaluated by the microscope reference method, and our results seemed to validate the hypotheses that the STKR model counts: i) eosinophils, basophils and banded neutrophils among GR; ii) variant lymphocytes among LY, and iii) various abnormal cells among mononuclear cells. However, in spite of this statistical significance, some difficulties in correctly classifying the mononuclear population were demonstrated.

Rapid assessment of fetal hemoglobin concentration with the HemoCue system.

Successful treatment of severe fetal hemolytic disease depends on rapid and accurate measurement of fetal hemoglobin or hematocrit. The HemoCue is a portable hemoglobinometer that rapidly measures hemoglobin concentration. To evaluate the potential role of this instrument in fetal transfusion therapy, we measured hemoglobin concentration with the HemoCue and compared it with Coulter counter determination of hemoglobin in 39 fetuses. The HemoCue accurately measured fetal hemoglobin concentration (y = -0.3986 + 1.0276x; r = 0.97, P less than .001). This instrument is valuable for use with intravascular fetal transfusions.

[Usefulness of cytometry based on the diffraction of a laser beam in evaluating spherocytosis]. / Utilidad de la citometría basada en la difracción de un haz de luz láser en la valoración de la esferocitosis.

Thirty four cases of hereditary spherocytosis were studied by means of laser diffraction cytometry. The cases were grouped for study in accordance to previous splenectomy or not, familial involvement or not, and, in patients not subjected to splenectomy, severity of the clinical course. The values used to assess the presence of spherocytosis were those measuring the haemoglobin concentration within red cells, such as CH (directly estimated mean corpuscular haemoglobin), HDW (standard deviation of the distribution according to haemoglobin concentration) and % hyper (percentage of cells with haemoglobin concentration higher than 41 g/dL). The variables attained were statistically analysed by means of non-parametric tests. In patients with spherocytosis, MCV, MCHC, RDW, HDW, % hyper, and CH were significantly different from the normal group. This method points to the presence of spherocytosis by means of CH, HDW and % hyper. A reduction of the limit of haemoglobin concentration used to define % hyper (41 g/dL) could improve the sensitivity of the instrument for the diagnosis of the mild forms, which is often more difficult.