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.

Reducing blood testing in pediatric patients after heart surgery: a quality improvement project.

OBJECTIVES: To safely optimize blood testing and costs for pediatric cardiac surgical patients without adversely impacting patient outcomes. DESIGN: This is a quality improvement cohort project with pre- and postintervention groups. SETTING: University-affiliated pediatric cardiac ICU in a tertiary care children's hospital. PATIENTS: All patients were surgical patients for whom Risk Adjustment for Congenital Heart Surgery categories allowed for stratification by complexity. The preintervention group was treated in 2010 and the postintervention group in 2011. INTERVENTIONS: Laboratory ordering processes were analyzed, and practice changed to limit standing blood test orders and requires individualized ordering. MEASUREMENTS AND MAIN RESULTS: Three hundred nineteen patients were studied in 2010 and 345 in 2011. Groups were similar in median age, weight, length of stay (ICU length of stay), and Risk Adjustment for Congenital Heart Surgery category. There was a reduction in the total blood tests per patient (24 vs 38; p < 0.0001) and length of stay adjusted tests per patient-day (10.4 vs 14.4; p = 0.0001) in the postintervention group. The largest test reductions were blood gases and single electrolytes. Adverse outcomes, such as extubation failure (6.4% vs 5.6%), central catheter-associated bloodstream infection (2.2 vs 1.5), and hospital mortality (0.6% vs 0.6%), were not significantly different between the groups. Cost analysis demonstrated an overall laboratory cost savings of 32%. In addition, the volume of packed RBC transfusions was also significantly decreased in the postintervention group among the most complex patients (Risk Adjustment for Congenital Heart Surgery, 6). CONCLUSIONS: Blood testing rates were safely decreased in postoperative pediatric cardiac patients by changing laboratory ordering practices. In addition, packed RBC transfusion was decreased among the most complex patients.

[Costs of delivering allogenic blood in hospitals]. / Kosten der Verabreichung von Blutkonserven im Krankenhaus.

INTRODUCTION: In clinical practice there are medical and economic reasons against the thoughtless use of packed red blood cells (rbc). Therefore, in searching for alternatives (therapy of anemia) the total costs of allogeneic blood transfusions must be considered. Using a practical example this article depicts the actual costs and possible alternatives from the point of view of a hospital in Germany. METHOD: To determine the total costs of allogeneic blood transfusions the actual resource consumption associated with blood transfusions was collated and analyzed at the St. Marien-Hospital in Vechta. RESULTS: The authors were able to show that the actual procurement costs (average. 97 EUR) represent only 55 % of the total costs of 176 EUR. The additional expenses are allocated to personnel (78 %) and materials (22 %). Alternatives, such as i.v. iron substitution or stimulation of erythropoesis might be the more economical solution especially if only purchase prices are compared and the total costs of allogeneic blood transfusions are not considered. DISCUSSION: Analyzing a single hospital limits generalization of the results; however, in the international context the results can be recognized as plausible. So far there have been no comprehensive studies on the true costs of blood preparations, therefore, this article represents a first starting point for closing this gap by conducting additional studies.

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.

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.

[Anaemia in a school of rural Cambodia: detection, prevalence, and links with intestinal worms and malnutrition]. / Anémie dans une école du Cambodge rural: détection, prévalence et liens avec les parasitoses intestinales et la malnutrition.

According to WHO, half of the world's children suffers from anaemia, which is a silent and neglected endemic resulting from three major causes: iron deficiency intestinal worms and malaria. A two month transversal study was conducted in a rural primary school in Battambang Province, Cambodia, in a malaria-free area. The main objective of the study was to assess the prevalence of anaemia and two of its possible driving factors, intestinal parasites and general malnutrition; a secondary objective was to assess the accuracy of haemoglobin colour scale, an easy and cheap visual technique compared to spectrophotometry used as the reference. Among 168 school children (average age: 11), the prevalence rates of moderate and severe anaemia were 24% and nil respectively; average haemoglobin was 12.6 g/dl. These results compared favourably with previous data from Cambodia. In our study's conditions, the haemoglobin colour scale grossly overestimated the anaemia prevalence: 83 vs. 24%, specificity 22%. Despite its simplicity and very low cost, this technique appeared inaccurate. Anaemia was independently associated with Ancylostoma carriage (p = 0.05), and stunting (p = 0.01), which prevalences were 54% et 40% respectively; and this, despite a mebendazole 500 mg dose given 9 months prior to the study as part of a regular deworming school program. Although periodical mass deworming in schools does not prevent early Ancylostoma reinfection, it may reduce the severity of anaemia. It therefore appears fully justified, and may be strengthened, notably by switching from mebendazole to albendazole.

International collaborative assessment study of the AHD575 method for the measurement of blood haemoglobin.

Accurate, economical methods for haemoglobin determination by laboratories in countries with limited resources are not available. This report provides the results of an international collaborative study evaluating the alkaline haematin detergent (AHD575) method as a reference method for laboratory services with limited resources. The study included 6 laboratories; 3 in East Mediterranean countries, 1 in East Africa and 3 in Europe. The (AHD575) method was evaluated against the HiCN method, with blood samples drawn from healthy and sick subjects. The results indicate that the AHD575 method is suitable for measuring haemoglobin in laboratories at all levels.

Use of the WHO hemoglobin color scale in family welfare clinics in India.

A situation is reported for the use of the WHO color scale for the measurement of hemoglobin, which was introduced into India in 1996. Charity family welfare clinics held at a medical college hospital in North India offer free sterilization by tubal ligation under local anesthetic to women following a preliminary screening. An obligatory test of the hemoglobin level is required and must be above 7.0 g/dl for the operation. Some clinics attract large numbers, and the card gives a cheap, rapid and reasonably accurate test, adding to the smooth running and reduction of waiting time. It has proved satisfactory over a 2-year period; 2.3% of participants were shown to have a hemoglobin level of 7 g/dl or less.

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.

Evaluation and costs of different haemoglobin methods for use in district hospitals in Malawi.

AIMS: To evaluate the characteristics of manual haemoglobin methods in use in Malawi and provide evidence for the Ministry of Health in Malawi to enable them to choose a suitable method for district hospitals. METHODS: Criteria on accuracy, clinical usefulness, user friendliness, speed, training time, and economic costs were determined by local health professionals and used to compare six different manual haemoglobin methods. These were introduced sequentially into use in a district hospital in Malawi alongside the reference method. RESULTS: HemoCue was the optimal method based on most of the outcome measures but was also the most expensive (0.75 US dollars/test). DHT meter and Jenway colorimeter were the second choice because they were cheaper (0.20-0.35 US dollars/test), but they were not as accurate or user friendly as HemoCue. CONCLUSIONS: The process for choosing appropriate laboratory methods is complex and very little guidance is available for health managers in poorer countries. This paper describes the development and testing of a practical model for gathering evidence about test efficiency that could be adapted for use in other resource poor settings.

Tests of glycemia for the diagnosis of type 2 diabetes mellitus.

This paper discusses tests of glycemia for the diagnosis of type 2 diabetes mellitus, with particular reference to the 1997 diagnostic criteria of the American Diabetes Association. The potential benefits of the lower diagnostic threshold for fasting plasma glucose are not well defined. However, the change in the diagnostic cut-off for diabetes mellitus affects as many as 1.9 million persons in the United States; therefore, the medical and social costs of the lower threshold may be considerable. Type 2 diabetes mellitus is defined by a threshold imposed on the continuous distribution of glycemic levels, typically with respect to risk for microvascular complications. However, the burden of type 2 diabetes relates more to macrovascular than microvascular complications. Because no clear threshold exists for macrovascular complications, a formal balancing of direct and indirect costs with both microvascular and macrovascular complications may be appropriate to establish glycemic thresholds. Because fasting plasma glucose, hemoglobin A1c, and the oral glucose tolerance test all predict diabetic complications yet test reliability is better for fasting plasma glucose and hemoglobin A1c than for the oral glucose tolerance test, we suggest an alternative diagnostic approach: If random plasma glucose is elevated (> or =11.1 mmol/L [200 mg/dL]) and the hemoglobin A1c level is more than 2 SDs above the laboratory mean, then diabetes mellitus should be diagnosed, and management should be based on the hemoglobin A1c level. If the result of only one of these tests is positive, then fasting plasma glucose should be tested to evaluate the patient for impaired fasting glucose and diabetes mellitus. The glycemic threshold for type 2 diabetes should be established by cost-effectiveness analysis. The clinical diagnosis of diabetes mellitus could be streamlined by incorporation of hemoglobin A1c into established criteria.

Field evaluation of who hemoglobin color scale in West Java.

The results obtained with a WHO hemoglobin (Hb) colour scale were evaluated in a field study in Chibubur district in Java island by comparison with hemoglobin values obtained by an automated blood cell analyzer K-800 (Sysmex. Kobe, Japan). When the color scale test was performed following the instructions for use. Hb values observed were usually higher than the values obtained by the analyzer. Thirty microl blood was loaded on the filter paper and an 60 sec waiting period was used. The sensitivity of results obtained with the color scale was 23.3% (14/60), and specificity was 96.6% (58/60). We propose an additional testing method based on our results.

An inexpensive and reliable new haemoglobin colour scale for assessing anaemia.

AIM: To describe a new inexpensive method (the WHO Colour Scale) for estimating haemoglobin concentration from a drop of blood by means of a colour scale, and to compare its reliability with a standard laboratory method of measuring haemoglobin, and its clinical usefulness in field trials. METHODS: The new colour scale method was used to measure haemoglobin concentration in 1213 random venous blood samples from routine work in four laboratories (one each in the UK, South Africa, Thailand, and Switzerland). Limited field trials of the method for assessing clinical usefulness were done in a rural hospital (in South Africa) staffed by nurses, at two blood donor sessions (one each in South Africa and Thailand), and by nonlaboratory personnel in malaria clinics (in Thailand), following training and a short practice session. RESULTS: In the laboratory based comparability study the presence of anaemia was reliably detected using the new method with 91% sensitivity and 86% specificity. Clinically relevant levels of anaemia (mild to moderate, pronounced, and severe) were graded and serious anaemia (< 8 g/dl) was identified with an efficiency of 89%. The clinical trials showed the ease and reliability with which the colour scale could be used by non-laboratory persons after brief training. The blood donor trials showed it to be at least as reliable as the copper sulphate method with the advantage of being more convenient. CONCLUSIONS: The preliminary studies have shown that the WHO Colour Scale is a reliable screening method for detecting anaemia, especially for diagnosing serious anaemia. Following a brief training session health workers found it simple to use and, at a cost of about 1/10th that for traditional photometric analysis, it should be of value in "countries in need" for primary health centres, obstetrical management, paediatric clinics, tropical disease control programmes, blood transfusion donor selection, as well as for industrial health checks and epidemiological studies.

[Routine determination of both hemoglobin and hematocrit is not necessary]. / Unødvendig med rutinemessig bestemmelse av både hemoglobin og hematokrit.

It is a well known fact that the haemoglobin concentration and haematocrit vary in proportion to one another in most clinical situations. Therefore routine, simultaneous measurement should not be necessary. In 400 consecutive patients' blood samples, a strong correlation between the two variables is demonstrated. Routine, simultaneous measurement of the haemoglobin concentration and haematocrit increases the workload and should be avoided.

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.