Evaluation of a portable hemoglobin photometer in pregnant women in a high altitude area: a pilot study

Diagnostic Accuracy of HemotypeSC as a Point-of-Care Testing Device for Sickle Cell Disease: Findings from a Southwestern State in Nigeria and Implications for Patient Care in Resource-Poor Settings of sub-Saharan Africa

This study aimed to determine the performance of a rapid, point-of-care testing device (HemotypeSC)™ for diagnosing sickle cell disease (SCD) relative to 2 commonly-used methods compared to DNA polymerase chain reaction (PCR) as the reference standard. The diagnostic performance of (HemotypeSC)™ in diagnosing SCD and determining various other Hb genotypes relative to high performance liquid chromatography (HPLC) and cellulose acetate Hb electrophoresis in alkaline buffer (CAE) was investigated among 156 participants aged 4 to 23 years in Ekiti, Southwest Nigeria. PCR was considered as the reference method/gold standard. The sensitivity and specificity for SS, SC, AS, AC, and AA genotypes by HemotypeSC and HPLC when compared with PCR, were each 100%. Similarly, their positive and negative predictive values were each 100%. However, sensitivity and specificity for identifying these Hb genotypes by CAE were 100, 100, 96.5, 0, 99.2%, and 99, 100, 92.9, 0, 91.7%. Also, CAE did not identify any of the 2 HbAC individuals that were correctly identified by PCR and both HemotypeSC, and HPLC, thus representing 100% HbAC misdiagnosis. In conclusion, this study shows that HemotypeSC has perfect concordance with PCR and 100% accuracy in diagnosing SCD in the population tested. Its ease of use, accuracy and other attributes make it suitable for use in sub-Saharan Africa for rapid determination of Hb genotypes.

Challenges in detection of adolescent anaemia: validation of point-of-care device (Mission® plus) for haemoglobin measurement among tribal residential school children of selected districts of Odisha, India

Background:

Screening for anemia among tribal school children has been a challenge.

Objectives:

To validate a point-of-care (POC) device (mission^® plus hemoglobinometer) to the gold standard method, spectrophotometry.

Study Design:

Cross-sectional study.

Participants:

The representative sample of 953 tribal adolescents from the residential schools of Odisha.

Methods:

Hemoglobin was measured simultaneously by the POC and gold standard method during January to July 2019. The validity of the POC device was measured by sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The area under the curve was calculated using receiver operating characteristic (ROC) analysis. Concordance of the POC device with the gold standard method was determined by the Bland–Altman plot. The intraclass correlation coefficient (ICC), precision (⍴), a bias correction factor (C_b), and the concordance correlation coefficient were also calculated. Deming regression analysis was performed, and a linear equation was established.

Results:

The mean age of the study participants was 13.07 (±1.48) years. The prevalence of anemia was 45.54% by the gold standard method. The sensitivity and specificity of the POC device were 94.9% and 56.1%, respectively. PPV and NPVs were 64.4% and 93.0%, respectively. The area under the ROC curve was found to be 0.856. The ICC was 0.887 (95% confidence interval: 0.872–0.901).

Conclusions:

Very good reliability/absolute agreement for hemoglobin measurements existed between the POC device and the gold standard method making it suitable as a screening device.

Variability in haemoglobin concentration by measurement tool and blood source: an analysis from seven countries

OBJECTIVE

We explore factors such as the blood sampling site (capillary vs venous), the equipment (HemoCue vs automated haematology analyser) and the model of the HemoCue device (201+ vs 301) that may impact haemoglobin measurements in capillary and venous blood.

METHODS

Eleven studies were identified, and bias, concordance and measures of diagnostic performance were assessed within each study.

FINDINGS

Our analysis included 11 studies from seven countries (Cambodia, India, The Gambia, Ghana, Laos, Rwanda and USA). Samples came from children, men, non-pregnant women and pregnant women. Mean bias ranged from -8.7 to 2.5 g/L in Cambodian women, 6.2 g/L in Laotian children, 2.4 g/L in Ghanaian women, 0.8 g/L in Gambian children 6-23 months and 1.4 g/L in Rwandan children 6-59 months when comparing capillary blood on a HemoCue to venous blood on a haematology analyser. Bias was 8.3 g/L in Indian non-pregnant women and 2.6 g/L in Laotian children and women and 1.5 g/L in the US population when comparing capillary to venous blood using a HemoCue. For venous blood measured on the HemoCue compared with the automated haematology analyser, bias was 5.3 g/L in Gambian pregnant women 18-45 years and 11.3 g/L in Laotian children 6-59 months.

CONCLUSION

Our analysis found large variability in haemoglobin concentration measured on capillary or venous blood and using HemoCue Hb 201+ or Hb 301 or automated haematology analyser. We cannot ascertain whether the variation is due to differences in the equipment, differences in capillary and venous blood, or factors affecting blood collection techniques.

Hemoglobin point-of-care testing in rural Gambia: Comparing accuracy of HemoCue and Aptus with an automated hematology analyzer

Background

Anemia is one of the most impactful nutrient deficiencies in the world and disproportionately affects children in low-resource settings. Point-of-care devices (PoCDs) measuring blood hemoglobin (Hb) are widely used in such settings to screen for anemia due to their low cost, speed, and convenience. Here we present the first iteration of Aptus, a new PoCD which measures Hb and hematocrit (HCT).

Aim

To evaluate the accuracy of Aptus and HemoCue® Hb 301 against an automated hematology analyzer (Medonic®) in Gambian children aged 6–35 months and the Aptus’ usage in the field.

Methods

Aptus, HemoCue® and Medonic® were compared using venous blood (n = 180), and Aptus and HemoCue® additionally using capillary blood (n = 506). Agreement was estimated using Bland-Altman analysis and Lin’s concordance. Usage was assessed by error occurrence and user experience.

Results

Mean Hb values in venous blood did not significantly differ between Aptus and HemoCue® (10.44±1.05 vs 10.56±0.93g/dl, p>0.05), but both measured higher Hb concentrations than Medonic® (9.75±0.99g/dl, p<0.0001). Lin’s coefficient between Aptus and Medonic® was r_c = 0.548, between HemoCue® and Medonic® r_c = 0.636. Mean bias between the PoCDs venous measurements was -0.11g/dl with limits of agreement (LoA) -1.63 and 1.40g/dl. The bias was larger for the comparisons between the Medonic® and both Aptus (0.69g/dl, LoA 0.92 and 2.31g/dl) and HemoCue® (0.81g/dl, LoA 0.17 and 1.78g/dl). ROC curves showed an AUC of 0.933 in HemoCue® and 0.799 in Aptus. Capillary Hb was higher with Aptus than HemoCue® (10.33±1.11g/dl vs 10.01±1.07g/dl, p<0.0001). Mean bias was 0.32g/dl with LoA of -1.91 and 2.54g/dl. Aptus‘ usage proved intuitive, yet time-to-results and cuvettes could be improved.

Conclusion

Both PoCDs showed a relatively limited bias but large LoA. Aptus and HemoCue® showed similar accuracy, while both overestimated Hb levels. Aptus showed promise, with its operation unimpaired by field conditions as well as being able to show HCT values.

Measurement of the Cellular Hemoglobin Concentration by Laser Scatter Method from Excessive Lipemic Sample: CASE REPORT

A 33-month old female child presented at a pediatric clinic with acute tonsillitis, and it was subsequently discovered that she had familial hyperlipidemia. Measurement of the patient's whole blood tests was performed by a multiparameter automated hematology analyzer, the CELLDYN Ruby System® (Abbott, Lake Forest, USA) using venous blood extracted from a tube containing 3.0 mL of EDTA. Although her hematocrit levels were within normal limits, the hemoglobin (Hgb) level, mean corpuscular volume (MCH) and mean corpuscular Hgb concentration (MCHC) could not be determined using the spectrophotometric method. The results of these tests could not be measured when repeated using dilution. When the sample was left to rest for several minutes, it was observed to be excessively lipemic. The measurements were repeated using the Alinity HQ Analyzer® (Abbott), which determines Hgb concentration using laser scatter and spectrophotometry. Hgb cellular concentration was incorrectly measured as being 21.9 mg/dL using routine spectrophotometry (denoted by a flag indicating Hgb interference) and correctly found to be 10.8 mg/dL. Thus, in samples of excessive lipemia, Hgb, MCH, and MCHC levels cannot be measured accurately using spectrophotometry. Hematology analyzers that can measure cellular hemoglobin (cHGB) and average erythrocyte hemoglobin concentration (cHCM) by laser scatter method may be recommended when analyzing a blood sample that contains excessive lipemia.

Hemoglobin levels and anemia evaluation among pregnant women in the remote and rural high lands of mid-western Nepal: a hospital based study

Background

Anemia though is a major risk factor for unfavorable pregnancy outcomes; no previous studies have yet described the hemoglobin (Hb) concentrations and anemia prevalence among pregnant women of remote mid western highlands of Nepal where the aggravating factors that increase the risk of anemia are very common. In addition, the physiological adaptive Hb rise to altitude was considered in the study while evaluating anemia. Thus, our primary objectives were to study the hemoglobin levels and prevalence of anemia among pregnant women of Jumla and its adjoining districts, and to assess the potential associations of hemoglobin and anemia with women’s characteristics.

Methods

The study was conducted in 319 singleton term non-smoker pregnant women who visited to the teaching hospital for delivery. Their blood samples were tested for Hb and related sociodemographic information was collected. One-way analysis of variance (ANOVA) and independent t-test were used to compare the mean Hb levels. Multiple linear regression model and multiple logistic regression model were used to assess the association of Hb level and anemia with pregnant women’s characteristics. The prevalence of anemia was calculated based on the altitude and pregnancy-adjusted Hb cut off value for anemia [{11+ adjustment factor (1.3)} gm./dl].

Results

The overall mean hemoglobin concentration was (13.497 ± 1.64) gm/dl, ranging from 8 to 19.20 g/dl. The pregnant women Hb level showed significant association with their age (Coeff = 0.059; 95% CI: 0.011, 0.106; p = 0.015) and parity (Coeff = − 0.21; 95% CI: − 0.382, − 0.038; p = 0.017). The overall prevalence of anemia in the study population was 17.9% (57/319), which varied with age, parity and ethnicity. The disadvantaged Janajatis were more likely (OR = 4.615, 95% CI: 1.48, 14.35, p = 0.008) to have anemia compared to upper cast group.

Conclusion

The mean Hb concentration was high and prevalence rate of anemia was low among pregnant women in karnali zone compared to average Nepali pregnant women. Women’s age and parity were significant predictors of Hb level. Ethnicity, however, was associated with the occurrence of anemia.

Evaluation of new non-invasive & conventional invasive methods of haemoglobin estimation in blood donors

Background & objectives:

The non-invasive method of haemoglobin (Hb) estimation has unique advantages of exemption of finger prick and associated pain, over invasive methods. This study was done to compare invasive and non-invasive methods of Hb estimation in blood donors keeping haematology analyzer (HA) as a reference method.

Methods:

The blood donors selected or deferred on the basis of CuSO₄ method (Hb ≥12.5 g/dl), were included in the study. Hb values of the donors were estimated by HemoCue and then by OrSense methods. An immediate post-donation venous sample was drawn for analysis on HA.

Results:

The mean Hb value was 13.98±1.27 g/dl on HA, 14.87±1.03 g/dl on OrSense and 15.03±1.31 g/dl on HemoCue. CuSO₄, HemoCue and OrSense demonstrated sensitivities of 18.7, 18.7 and 13.1 per cent, positive predictive values (PPV) of 64.5, 83.3 and 60.9 per cent and specificities of 98.9, 99.6 and 99.1 per cent, respectively. The intra-class correlation coefficient for OrSense was 0.726 while that for HemoCue was 0.851. Bland-Altman plots demonstrated 2SD difference of >2.0 g/dl in Hb estimations between HA and HemoCue/OrSense.

Interpretation & conclusions:

The non-invasive modality may provide the near-ideal pre-donation Hb screening platform if an improvement can be done in the sensitivity and PPV of the non-invasive method keeping in view its unique advantages.

Comparison of three-fold converted hematocrit and micro-hematocrit in pregnant women

BACKGROUND

Anemia is one of the common complications of pregnancy. Hemoglobin concentration, Hematocrit, and Red cell count are laboratory tests used to diagnose anemia. In are source poor setting, there is a practice of using three-fold converted Hematocrit. This study is designed to assess the association and acceptability of three-fold converted Hematocrit as compared to the standard Micro-hematocrit method, in pregnant women.

METHOD

The cross-sectional study conducted from May 18 to June 12, 2018 involved 200 pregnant women who visited the Laboratory for a Hematocrit test. Three milliliter of venous blood was collected with EDTA tube to determine Hematocrit by the Micro-hematocrit method and Hemoglobin concentration measured by a HemoCue Hemoglobin B analyzer. A scatter plot, correlation coefficient, Bland and Altman plot, and Area under curve were employed to assess the agreement and acceptability of the calculated Hematocrit as compared to the standard Micro-hematocrit.

RESULT

The correlation coefficient, Intraclass correlation coefficient and concordance correlation coefficient were 0.91, 0.94, and 0.89, respectively. The Bland and Altman plot showed a mean difference of 0.94 with the limit of agreement ranges from 0.6 to 1.3. The area under the receiver operating characteristics with cut-off point of Hematocrit <33% was 0.86. The sensitivity and specificity of the calculated method was 95.5% and 71.4%, respectively.

CONCLUSION

Generally there is excellent association between the two methods. The two methods were identical within inherent imprecision of both methods. Hence, the Hematocrit value, threefold calculated from the Hemoglobin was found to be acceptable to diagnose anemia in pregnant women.

Methods and analyzers for hemoglobin measurement in clinical laboratories and field settings

This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. We conducted a literature review for methods used to measure Hb in clinical laboratories and field settings. We described methods to measure Hb and factors influencing results. Automated hematology analyzer (AHA) was reference for all Hb comparisons using evaluation criteria of ±7% set by College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). Capillary fingerprick blood usually produces higher Hb concentrations compared with venous blood. Individual drops produced lower concentrations than pooled capillary blood. Compared with the AHA: (1) overall cyanmethemoglobin (1.0-8.0  g/L), WHO Colour Scale (0.5-10.0  g/L), paper-based devices (5.0-7.0  g/L), HemoCue® Hb-201 (1.0-16.0  g/L) and Hb-301 (0.5-6.0  g/L), and Masimo Pronto® (0.3-14.0  g/L) overestimated concentrations; (2) Masimo Radical®-7 both under- and overestimated concentrations (0.3-104.0  g/L); and (3) other methods underestimated concentrations (2.0-16.0  g/L). Most mean concentration comparisons varied less than ±7% of the reference. Hb measurements are influenced by several analytical factors. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.

Comparison of Performance of Digital Hemoglobinometer over Automated Hematology Analyzer for Hemoglobin Estimation and Its user-friendliness among the Pregnant Women in Selected District Hospitals of Madhya Pradesh

Context:

There is a need for a simple screening method for the detection of anemia that can be used by public health workers in the field.

Aims:

The aim of this study was to compare two methods for hemoglobin estimation, i.e., automated hematology analyzer and Digital Hemoglobinometer, and to find out the sensitivity and specificity of Digital Hemoglobinometer for the estimation of hemoglobin.

Subjects and Methods:

A hospital-based cross-sectional study was carried out for 6 months from April to September 2017 in a District Hospital of five High Priority Districts of Madhya Pradesh. Two hundred and sixty antenatal females per district were selected for the study.

Results:

The mean hemoglobin by autoanalyzer is 10.19, and that by Digital Hemoglobinometer device is 9.89. Overall, sensitivity of Digital Hemoglobinometer for hemoglobin estimation was calculated to be 89.4% and specificity was calculated to be 63.6%. Positive predictive value was found to be 82.6% and negative predictive value was 75.8% compared against AutoAnalyser (gold standard).

Conclusions:

As the Digital Hemoglobinometer device has high sensitivity and specificity and good diagnostic accuracy, it must be used at the community level in resource-poor setting for hemoglobin estimation. In primary health-care conditions, Digital Hemoglobinometer can significantly reduce misdiagnosis of anemia compared with clinical assessment alone.

Assessment of the diagnostic performance of TrueHb® point-of-care hemometer compared with Sysmex i3 analyzer among patients at International Hospital Kampala, Uganda

Aim/Objective: To assess the diagnostic performance of TrueHb® point-of-care (POC) hemometer compared with Sysmex i3 analyzer at International Hospital Kampala, Uganda. Materials and methods: We analyzed ethylenediaminetetraacetic acid blood samples to estimate hemoglobin (Hb) levels using parallel testing with TrueHb® hemometer and Sysmex i3 analyzer. Data were analyzed to ascertain the diagnostic performance of the test assays using the Bland and Altman method. Sensitivity, specificity, positive and negative predictive values were calculated. Results: The study enrolled 402 patients; of these, 156 (38.8%) were males. The average Hb levels were 8.7±1.8 and 13.3±2.6 g/dL for the anemic and nonanemic patients, respectively. One hundred and fifty-five participants were anemic, giving anemia prevalence of 38.56% (95% CI: 35.17-40.38). The mean difference of the TrueHb® and Sysmex i3 assays was 2.2219 (SD 1.07915), and the two devices did not show a difference in their measurements (t=-2.407, p-value 0.017, 95% CI: -0.095-0.010). Further, they showed a significant level of agreement (t=41.281; 95% CI: 2.1161-2.3277) and intraclass correlation coefficients (ICC=0.793). The sensitivity, specificity, positive and negative predictive values were 100.00%, 51.01%, 55.16% and 100.00%, respectively. The average performance turnaround time (TAT) for the TrueHb® hemometer was 2.46 mins (95% CI: 2.37-2.55). Conclusion: TrueHb® POC hemometer is an accurate POC for Hb estimation with a good performance agreement with the Sysmex i3 analyzer. This, coupled with its utility aspects, makes it a good diagnostic tool in a high anemia burden and low-resource setting.

Measurement and interpretation of hemoglobin concentration in clinical and field settings: a narrative review

Anemia affects over 800 million women and children globally. Defined as a limited or insufficient functional red blood cell supply in peripheral blood, anemia causes a reduced oxygen supply to tissues and can have serious health consequences for women and children. Hemoglobin (Hb) concentration is most commonly measured for anemia diagnosis. Methods to measure Hb are usually invasive (requiring a blood sample); however, advances in diagnostic and clinical chemistry over the past decade have led to the development of new noninvasive methods. Accurate diagnosis at the individual level is important to identify individuals who require treatment. At the population level, anemia prevalence estimates are often the impetus for national nutrition policies or programs. Thus, it is essential that methods for Hb measurement are sensitive, specific, accurate, and reproducible. The objective of our narrative review is to describe the basic principles, advantages, limitations, and quality control issues related to methods of Hb measurement in clinical and field settings. We also discuss other biomarkers and tests that can help to determine the severity and underlying causes of anemia. In conclusion, there are many established and emerging methods to measure Hb concentration, each with their own advantages, limitations, and factors to consider before use.

Comparison of haemoglobin estimates using direct & indirect cyanmethaemoglobin methods

Background & objectives:

Estimation of haemoglobin is the most widely used method to assess anaemia. Although direct cyanmethaemoglobin method is the recommended method for estimation of haemoglobin, but it may not be feasible under field conditions. Hence, the present study was undertaken to compare indirect cyanmethaemoglobin method against the conventional direct method for haemoglobin estimation.

Methods:

Haemoglobin levels were estimated for 888 adolescent girls aged 11-18 yr residing in an urban slum in Delhi by both direct and indirect cyanmethaemoglobin methods, and the results were compared.

Results:

The mean haemoglobin levels for 888 whole blood samples estimated by direct and indirect cyanmethaemoglobin method were 116.1 ± 12.7 and 110.5 ± 12.5 g/l, respectively, with a mean difference of 5.67 g/l (95% confidence interval: 5.45 to 5.90, P<0.001); which is equivalent to 0.567 g%. The prevalence of anaemia was reported as 59.6 and 78.2 per cent by direct and indirect methods, respectively. Sensitivity and specificity of indirect cyanmethaemoglobin method were 99.2 and 56.4 per cent, respectively. Using regression analysis, prediction equation was developed for indirect haemoglobin values.

Interpretation & conclusions:

The present findings revealed that indirect cyanmethaemoglobin method overestimated the prevalence of anaemia as compared to the direct method. However, if a correction factor is applied, indirect method could be successfully used for estimating true haemoglobin level. More studies should be undertaken to establish agreement and correction factor between direct and indirect cyanmethaemoglobin methods.

Point-of-Care Testing for Anaemia in Children Using Portable Haematocrit Meter: A Pilot Study from Southwest Nigeria and Implications for Developing Countries

Background

Prompt and accurate diagnosis is needed to prevent the untoward effects of anaemia on children. Although haematology analyzers are the gold standard for accurate measurement of haemoglobin or haematocrit for anaemia diagnosis, they are often out of the reach of most health facilities in resource-poor settings thus creating a care gap. We conducted this study to examine the agreement between a point-of-care device and haematology analyzer in determining the haematocrit levels in children and to determine its usefulness in diagnosing anaemia in resource-poor settings.

Methods

EDTA blood samples collected from participants were processed to estimate their haematocrits using the two devices (Mindray BC-3600 haematology analyzer and Portable Mission Hb/Haemotocrit testing system). A pairwise t-test was used to compare the haematocrit (PCV) results from the automated haematology analyzer and the portable haematocrit meter. The agreement between the two sets of measurements was assessed using the Bland and Altman method where the mean, standard deviation and limit of agreement of paired results were calculated.

Results

The intraclass and concordance correlation coefficients were 0.966 and 0.936. Sensitivity and specificity were 97.85% and 94.51% respectively while the positive predictive and negative predictive values were 94.79% and 97.73%. The Bland and Altman`s limit of agreement was −5.5–5.1 with the mean difference being −0.20 and a non-ignificant variability between the two measurements (p = 0.506).

Conclusion

Haematocrit determined by the portable testing system is comparable to that determined by the haematology analyzer. We therefore recommend its use as a point-of-care device for determining haematocrit in resource-poor settings where haematology analyzers are not available.

Evaluation of a Portable Haemoglobin Metre Performance in Children with Sickle Cell Disease and Implications for Healthcare in Resource-poor Settings

BACKGROUND

Sub-Saharan Africa has the largest burden and worst outcome of sickle cell disease (SCD). This gloomy outlook has been attributed to the lack of use of simple and cost-effective measures for diagnosis and treatment of the disease. Although haematology analysers are the gold standard for accurate measurement of haemoglobin (Hb) concentration, they are often out of reach of most health facilities in resource-poor settings, thus creating a care gap. We conducted this study to examine the agreement between a point-of-care device and haematology analyser for determining the Hb concentration in children with SCD and its usefulness in resource-poor settings.

METHODS

Ethylenediaminetetraacetic acid blood samples collected from participants were processed to estimate their Hb concentration using two devices (Sysmex KX21N haematology analyser and portable mission Hb device). The agreement between the two sets of measurements was assessed by the Bland and Altman method.

RESULTS

The intraclass and concordance correlation coefficients were 0.854 and 0.936, respectively. Sensitivity and specificity were 84.2% and 98.6%, respectively. The positive and negative predictive values were 94.1% and 96.0%, respectively. The Bland and Altman's limit of agreement was -2.3 to 1.6 and the mean difference was -0.34 with non-significant variability between the two measurements (p  =  0.949).

CONCLUSION

Hb concentration determined by the portable testing system is comparable with that determined by the haematology analyser. We recommend its use as a point-of-care device for determining Hb concentration of SCD children in resource-poor settings where haematology analysers are not available.

Noninvasive Assessment of Excessive Erythrocytosis as a Screening Method for Chronic Mountain Sickness at High Altitude

Vyas, Kaetan J., David Danz, Robert H. Gilman, Robert A. Wise, Fabiola León-Velarde, J. Jaime Miranda, and William Checkley. Noninvasive assessment of excessive erythrocytosis as a screening method for chronic mountain sickness at high altitude. High Alt Med Biol 16:162-168, 2015.--Globally, over 140 million people are at risk of developing chronic mountain sickness, a common maladaptation to life at high altitude (>2500 meters above sea level). The diagnosis is contingent upon the identification of excessive erythrocytosis (EE). Current best practices to identify EE require a venous blood draw, which is cumbersome for large-scale surveillance. We evaluated two point-of-care biomarkers to screen for EE: noninvasive spot-check tests of total hemoglobin and oxyhemoglobin saturation (Pronto-7, Masimo Corporation). We conducted paired evaluations of total serum hemoglobin from a venous blood draw and noninvasive, spot-check testing of total hemoglobin and oxyhemoglobin saturation with the Pronto-7 in 382 adults aged ≥35 years living in Puno, Peru (3825 meters above sea level). We used the Bland-Altman method to measure agreement between the noninvasive hemoglobin assessment and the gold standard lab hemoglobin analyzer. Mean age was 58.8 years and 47% were male. The Pronto-7 test was unsuccessful in 21 (5%) participants. Limits of agreement between total hemoglobin measured via venous blood draw and the noninvasive, spot-check test ranged from -2.8 g/dL (95% CI -3.0 to -2.5) to 2.5 g/dL (95% CI 2.2 to 2.7), with a bias of -0.2 g/dL (95% CI -0.3 to -0.02) for the difference between total hemoglobin and noninvasive hemoglobin concentrations. Overall, the noninvasive spot-check test of total hemoglobin had a better area under the receiver operating characteristic curve compared to oxyhemoglobin saturation for the identification of EE as measured by a gold standard laboratory hemoglobin analyzer (0.96 vs. 0.82; p<0.001). Best cut-off values to screen for EE with the Pronto 7 were ≥19.9 g/dL in males and ≥17.5 g/dL in females. At these cut-points, sensitivity and specificity were both 92% and 89% for males and females, respectively. A noninvasive, spot-check test of total hemoglobin had low bias and high discrimination for the detection of EE in high altitude Peru, and may be a useful point-of-care tool for large-scale surveillance in high-altitude settings.

Systematic Review and Meta-Analysis of Method Comparison Studies of Masimo Pulse Co-Oximeters (Radical-7™ or Pronto-7™) and HemoCue® Absorption Spectrometers (B-Hemoglobin or 201+) with Laboratory Haemoglobin Estimation

We assessed agreement in haemoglobin measurement between Masimo pulse co-oximeters (Rad-7™ and Pronto-7™) and HemoCue® photometers (201+ or B-Hemoglobin) with laboratory-based determination and identified 39 relevant studies (2915 patients in Masimo group and 3084 patients in HemoCue group). In the Masimo group, the overall mean difference was -0.03 g/dl (95% prediction interval -0.30 to 0.23) and 95% limits of agreement -3.0 to 2.9 g/dl compared to 0.08 g/dl (95% prediction interval -0.04 to 0.20) and 95% limits of agreement -1.3 to 1.4 g/dl in the HemoCue group. Only B-Hemoglobin exhibited bias (0.53, 95% prediction interval 0.27 to 0.78). The overall standard deviation of difference was larger (1.42 g/dl versus 0.64 g/dl) for Masimo pulse co-oximeters compared to HemoCue photometers. Masimo devices and HemoCue 201+ both provide an unbiased, pooled estimate of laboratory haemoglobin. However, Masimo devices have lower precision and wider 95% limits of agreement than HemoCue devices. Clinicians should carefully consider these limits of agreement before basing transfusion or other clinical decisions on these point-of-care measurements alone.

Evaluation of hemoglobin concentration in pregnancy and correlation with different altitude: a study from balochistan plateau of pakistan

BACKGROUND

Anemia refers to a condition having low hemoglobin concentration. Anemia is considered a major risk factor for unfavorable pregnancy outcomes. This is the first study describing the pattern of hemoglobin concentration during pregnancy and its relationship to areas of high and low altitudes in Balochistan (the largest of Pakistan's four provinces). The main objective of this study was to observe hemoglobin levels and prevalence of anemia among pregnant women living in the high or low altitude areas of Balochistan.

METHODS

A randomized survey was conducted and blood samples were collected from 132 healthy full term pregnant women subjects and 110 unmarried females. The subjects of the current study were selected from two different areas of Balochistan (Quetta and Uthal). Hemoglobin levels of the subjects were analyzed on Microlab 300 by Merck kit. Dietary status of the subjects was assessed based on simplified associated food frequency questionnaire. The factors effecting hemoglobin in full term pregnancy at different altitudes were multi gravidity/parity (increased number of pregnancies/children), age, socio-economic and educational status.

RESULTS

Anemia was highly prevalent in low-altitude region (68.33%). We found statistically significant difference in mean hemoglobin level at high-altitude region (11.81 ± 1.02) and low-altitude region (10.20 ± 1.28) in pregnant females of Balochistan plateau (P < 0.001). Higher maternal age (> 35 years) has shown significantly higher anemic frequency at both high (57.89%; p < 0.002) and low (41.46%; p = 0.067) altitudes. A balanced-diet that is rich in meat products has also shown significant correlation with reduced incidences of anemia among pregnant women at both altitudes.

CONCLUSION

Hemoglobin concentration increases in the body with elevated altitudes and, thus, anemia was less frequent at high-altitude region. Factors affecting hemoglobin concentration in full term pregnancy at different altitudes included old maternal age, low body-mass index, education and diet.

Evaluation of two methods to measure hemoglobin concentration among women with genetic hemoglobin disorders in Cambodia: a method-comparison study

BACKGROUND

Genetic hemoglobin (Hb) E variants are common in Cambodia and result in an altered and unstable Hb molecule. We evaluated two methods to measure Hb concentration among individuals with and without Hb variants using a hemoglobinometer (HemoCue) and a hematology analyzer (Sysmex XT-1800i).

METHODS

We determined the bias and concordance between the methods among 420 Cambodian women (18-45 y).

RESULTS

Bias and concordance appeared similar between methods among women with no Hb disorders (n=195, bias=2.5, ρc=0.68), women with Hb E variants (n=133, bias=2.5, ρc=0.78), and women with other Hb variants (n=92, bias=2.7, ρc=0.73). The overall bias was 2.6g/l, resulting in a difference in anemia prevalence of 11.5% (41% using HemoCue and 29.5% using Sysmex, p<0.001). Based on visual interpretation of the concordance plots, the HemoCue device appears to underestimate Hb concentrations at lower Hb concentrations and to overestimate Hb concentrations at higher Hb concentrations (in comparison to the Sysmex analyzer).

CONCLUSIONS

Bias and concordance were similar across groups, suggesting the two methods of Hb measurement were comparable. We caution field staff, researchers and policy makers in the interpretation of data and the impact that bias between methods can have on anemia prevalence rates.

[Anesthetic management of severe or worsening postpartum hemorrhage]

INTRODUCTION

Risk factors of maternal morbidity and mortality during postpartum hemorrhage (PPH) include non-optimal anesthetic management. As the anesthetic management of the initial phase is addressed elsewhere, the current chapter is dedicated to the management of severe PPH.

METHODS

A literature search was performed using PubMed and Medline databases, and the Cochrane Library, for articles published from 2003 up to and including 2013. Several keywords related to anesthetic and critical care practice, and obstetrical management were used, in various combinations. Guidelines from several societies and organisations were also read.

RESULTS

When PPH worsens, one should ask for additional team personnel (professional consensus). Patients should be monitored for heart rate, blood pressure, skin and mucosal pallor, bleeding at skin puncture sites, diuresis and the volume of genital bleeding (grade B). Because of the possible rapid worsening of coagulapathy, patients should undergo regular evaluation of coagulation status (professional consensus). Prevention and management of hypothermia should be considered (professional consensus), by warming intravenous fluids and blood products, and by active body warming (grade C). Antibiotics should be given, if not already administered at the initial phase (professional consensus). Vascular fluids must be given (grade B), the choice being left at the physician discretion. Blood products transfusion should be decided based on the clinical severity of PPH (professional consensus). Priority is given to red blood cells (RBC) transfusion, with the aim to maintain Hb concentration>8g/dL. The first round of products could include 3 units of RBC (professional consensus), and the following round 3 units of RBC, and 3 units of fresh frozen plasma (FFP). The FFP:RBC ratio should be kept between 1:2 and 1:1 (professional consensus). Depending on the etiology of PPH, the early administration of FFP is left at the discretion of the physician (professional consensus). Platelet count should be maintained at>50 G/L (professional consensus). During massive PPH, fibrinogen concentration should be maintained at>2g/L (professional consensus). Fibrinogen can be given without prior fibrinogen measurement in case of massive bleeding (professional consensus). General anesthesia should be considered in case of hemodynamic instability, even when an epidural catheter is in place (professional consensus).

CONCLUSION

The anesthetic management aims to restore and maintain optimal respiratory state and circulation, to treat coagulation disorders, and to allow invasive obstetrical and radiologic procedures. Clinical and instrumental monitoring are needed to evaluate the severity of PPH, to guide the choice of therapeutic options, and to assess treatments efficacy.

Comparison of HemoCue® hemoglobin-meter and automated hematology analyzer in measurement of hemoglobin levels in pregnant women at Khartoum hospital, Sudan

Background

Assessment of hemoglobin is one of the most reliable indicators for anemia, and is widely used to screen for anemia among pregnant women. The HemoCue^® has been widely used for as a point-of-care device for hemoglobin estimation in health facilities. Previous studies showed contradictory results regarding the accuracy of HemoCue^®.

Methods

This was a hospital-based cross sectional study carried- out among pregnant women at Khartoum hospital in Sudan to find out whether the measurement of hemoglobin concentration by HemoCue^® using venous or capillary samples was comparable to that of the automated hematology analyzer as standard. Bland and Altman method was used to compare the measurements with an acceptable difference of ± 1.0 g/dl.

Results

Among the 108 subjects in this study the mean (SD) level of hemoglobin level using HemoCue^® venous sample, HemoCue^® capillary sample and automated hematology analyzer were 12.70 (1.77), 12.87 (2.04) and 11.53 (1.63) g/dl, respectively. Although the correlations between the measurements were all significant there was no agreement between HemoCue^® and automated hematology analyzer. The bias + SD (limits of agreement) for HemoCue^® venous versus hematology analyzer was 1.17 ± 1.57 (-1.97, 4.31) g/dl, HemoCue^® capillary versus hematology analyzer was 1.34 ± 1.85 (-2.36, 5.04) g/dl, and HemoCue^® venous versus HemoCue^® capillary samples was 017 ± 1.90 and (3.97-3.63) g/dl.

Conclusion

Hemoglobin concentration assessment by HemoCue^® using either venous or capillary blood samples has shown unacceptable agreement with automated hematology analyzer.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8797022296725036

Hemoglobin estimation by the HemoCue® portable hemoglobin photometer in a resource poor setting

Background

In resource poor settings where automated hematology analyzers are not available, the Cyanmethemoglobin method is often used. This method though cheaper, takes more time. In blood donations, the semi-quantitative gravimetric copper sulfate method which is very easy and inexpensive may be used but does not provide an acceptable degree of accuracy. The HemoCue^® hemoglobin photometer has been used for these purposes. This study was conducted to generate data to support or refute its use as a point-of-care device for hemoglobin estimation in mobile blood donations and critical care areas in health facilities.

Method

EDTA blood was collected from study participants drawn from five groups: pre-school children, school children, pregnant women, non-pregnant women and men. Blood collected was immediately processed to estimate the hemoglobin concentration using three different methods (HemoCue^®, Sysmex KX21N and Cyanmethemoglobin). Agreement between the test methods was assessed by the method of Bland and Altman. The Intraclass correlation coefficient (ICC) was used to determine the within subject variability of measured hemoglobin.

Results

Of 398 subjects, 42% were males with the overall mean age being 19.4 years. The overall mean hemoglobin as estimated by each method was 10.4 g/dl for HemoCue, 10.3 g/dl for Sysmex KX21N and 10.3 g/dl for Cyanmethemoglobin. Pairwise analysis revealed that the hemoglobin determined by the HemoCue method was higher than that measured by the KX21N and Cyanmethemoglobin. Comparing the hemoglobin determined by the HemoCue to Cyanmethemoglobin, the concordance correlation coefficient was 0.995 (95% CI: 0.994-0.996, p < 0.001). The Bland and Altman's limit of agreement was -0.389 - 0.644 g/dl with the mean difference being 0.127 (95% CI: 0.102-0.153) and a non-significant difference in variability between the two measurements (p = 0.843). After adjusting to assess the effect of other possible confounders such as sex, age and category of person, there was no significant difference in the hemoglobin determined by the HemoCue compared to Cyanmethemoglobin (coef = -0.127, 95% CI: -0.379 - 0.634).

Conclusion

Hemoglobin determined by the HemoCue method is comparable to that determined by the other methods. The HemoCue photometer is therefore recommended for use as on-the-spot device for determining hemoglobin in resource poor setting.