Training health workers to assess anaemia with the WHO haemoglobin colour scale

Outcome of a one-week intensive training workshop for veterinary diagnostic laboratory workers in Liberia

There is a huge unmet need for veterinary diagnostic laboratory services in developing nations such as Liberia. One way of bridging the service gap is for visiting experts to provide veterinary laboratory training to technicians in a central location in a short-course format. An intensive 1-week training workshop was organized for 18 student and faculty participants from the College of Agriculture and Integrated Development Studies (CAIDS) at Cuttington University in rural central Liberia. The training was designed and delivered by the non-governmental organization Veterinarians Without Borders US and funded through a Farmer-to-Farmer grant provided by the United States Agency for International Development. Although at the start of training none of the students had any veterinary laboratory experience, by the end of the course over 80% of the students were able to discuss appropriate care and use of a microscope and name at least three important components of laboratory record keeping; over 60% were able to describe how to make and stain a blood smear and how to perform a passive fecal flotation; and over 30% were able to describe what a packed cell volume is and how it is measured and name at least three criteria for classifying bacteria. The intensive training workshop greatly improved the knowledge of trainees about veterinary diagnostic laboratory techniques. The training provided initial skills to students and faculty who are awaiting the arrival of additional grant-funded laboratory equipment to continue their training.

Evaluation of the diagnostic accuracy of the Haemoglobin Colour Scale to detect anaemia in young children attending primary healthcare clinics in Zanzibar

OBJECTIVES

This study evaluates the diagnostic accuracy of Haemoglobin Colour Scale (HCS), compared with clinical diagnosis, to detect anaemia and severe anaemia in preschool-age children attending primary healthcare clinics in rural Zanzibar.

METHODS

In all participants, haemoglobin (Hb) concentration was independently estimated by clinical examination for palmar pallor, HCS and HemoCue™. HemoCue was considered the reference method. Data collection was integrated into the usual health services and performed by local healthcare workers (HCWs). Sensitivity, specificity, positive and negative predictive values were calculated for HCS and clinical examination for palmar pallor. The limits of agreement between HCS and HemoCue, and inter-observer variability for HCS, were also defined.

RESULTS

A total of 799 children age 2-59 months were recruited to the study. The prevalence of anaemia (Hb<11 g/dl) and severe anaemia (<5 g/dl) were 71% and 0.8% respectively. The sensitivity of HCS to detect anaemia was 33% [95% confidence interval (CI) 29-36] and specificity was 87% (83-91). The sensitivity of HCS to detect severe anaemia was 14% (95% CI 0-58) and specificity was 100% (99-100). The sensitivity of palmar pallor to detect anaemia was low, but superior to HCS (58% vs. 33%, P<0.001); specificity was inferior to HCS (55% vs. 87%, P<0.001). There was no evidence of a difference in either sensitivity (P>0.1) or specificity (P>0.1) between HCS and palmar pallor to detect severe anaemia.

CONCLUSIONS

Haemoglobin Colour Scale does not improve the capacity of HCWs to diagnose anaemia in this population. Accuracy is limited by considerable variability in the performances of test operators. However, optimizing the training protocol for those using the test may improve performance.

Enhancing the routine health information system in rural southern Tanzania: successes, challenges and lessons learned

OBJECTIVE

To describe and evaluate the use of handheld computers for the management of Health Management Information System data.

METHODS

Electronic data capture took place in 11 sentinel health centres in rural southern Tanzania. Information from children attending the outpatient department (OPD) and the Expanded Program on Immunization vaccination clinic was captured by trained local school-leavers, supported by monthly supervision visits. Clinical data included malaria blood slides and haemoglobin colour scale results. Quality of captured data was assessed using double data entry. Malaria blood slide results from health centre laboratories were compared to those from the study's quality control laboratory.

RESULTS

The system took 5 months to implement, and few staffings or logistical problems were encountered. Over the following 12 months (April 2006-March 2007), 7056 attendances were recorded in 9880 infants aged 2-11 months, 50% with clinical malaria. Monthly supervision visits highlighted incomplete recording of information between OPD and laboratory records, where on average 40% of laboratory visits were missing the record of their corresponding OPD visit. Quality of microscopy from health facility laboratories was lower overall than that from the quality assurance laboratory.

CONCLUSIONS

Electronic capture of HMIS data was rapidly and successfully implemented in this resource-poor setting. Electronic capture alone did not resolve issues of data completeness, accuracy and reliability, which are essential for management, monitoring and evaluation; suggestions to monitor and improve data quality are made.

Evaluating the effectiveness of IPTi on malaria using routine health information from sentinel health centres in southern Tanzania

BACKGROUND

Intermittent preventive treatment of malaria in infants (IPTi) consists of the administration of a treatment dose of sulphadoxine-pyrimethamine (SP) at the time of routine vaccinations. The use of routine Health Management and Information Services (HMIS) data to investigate the effect of IPTi on malaria, anaemia, and all-cause attendance in children aged 2-11 months presenting to 11 health centres in southern Tanzania is described.

METHODS

Clinical diagnosis of malaria was confirmed with a positive blood slide reading from a quality assurance laboratory. Anaemia was defined using two thresholds (mild [Hb<11 g/dL], severe [Hb<8 g/dL]). Incidence rates between IPTi and non-implementing health centres were calculated using Poisson regression, and all statistical testing was based on the t test due to the clustered nature of the data.

RESULTS

Seventy two per cent of infants presenting in intervention areas received at least one dose of IPTi--22% received all three. During March 2006-April 2007, the incidence of all cause attendance was two attendances per person, per year (pppy), including 0.2 episodes pppy of malaria, 0.7 episodes of mild and 0.13 episodes of severe anaemia. Point estimates for the effect of IPTi on malaria varied between 18% and 52%, depending on the scope of the analysis, although adjustment for clustering rendered these not statistically significant.

CONCLUSIONS

The point estimate of the effect of IPTi on malaria is consistent with that from a large pooled analysis of randomized control trials. As such, it is plausible that the difference seen in health centre data is due to IPTi, even thought the effect did not reach statistical significance. Findings draw attention to the challenges of robust inference of effects of interventions based on routine health centre data. Analysis of routine health information can reassure that interventions are being made available and having desired effects, but unanticipated effects should trigger data collection from representative samples of the target population.

Évaluation de deux techniques de dosage de l'hémoglobine chez des donneurs de sang camerounais

In order to identify a rapid feasible and adaptable method of haemoglobin measurement for use in a blood bank, two methods were evaluated against the automated method in 204 blood donors in Yaoundé, Cameroon. Anaemia was defined as Haemoglobin<12 g/dl. Using the World Health Organisation (WHO) haemoglobin colour scale (HCS), the Hemocue method (HemoCue AB, Angelhom, Suède) and the Celly Electronic counter (Hycel Diagnostics, Reims, France), anaemia was found in 27.5, 29.4 and 31.9% of donors respectively (P<0.05). The sensitivity and specificity of the HCS was 75.38 and 94.96% respectively compared to 86.15 and 97.13% respectively in the HemoCue method. Correlation studies between each method compared to automated method showed r=0.70 for the WHO. colour scale method and 0.91 for the Hemocue method. Using the Bland and Altman statistical method, the haemoglobin distribution around the mean was wider in the WHO scale (-2.74;+2.96) than in the Hemocue method (-2.06; +1.38). We conclude that while the two methods can be used to detect anaemia in the blood bank, that the Hemocue method is more sensitive and more specific.

Evaluation of the WHO Haemoglobin Colour Scale for diagnosis of anaemia in children and pregnant women as used by primary health care nurses and community health workers in western Kenya

OBJECTIVES

To evaluate the diagnostic accuracy of the WHO Haemoglobin Colour Scale (HCS) for anaemia in three groups of children aged 2 months to 2 years (sick children, those visiting an immunization clinic and a community-based random sample of children) and a sample of pregnant women.

METHODS

Finger-prick blood samples were taken from all consenting participants. Haemoglobin (Hb) levels from the HCS were compared with results from a HemoCue portable haemoglobinometer. Sensitivity, specificity and positive and negative predictive values for the HCS were calculated.

RESULTS

A total of 457 sick children, 336 children visiting immunization clinics, 454 children from the community at large and 643 pregnant women participated. The prevalence of anaemia (Hb<11 g/dl) in these groups was 87%, 79%, 74% and 52%, respectively. The prevalence of severe anaemia (Hb<7 g/dl) was 24%, 11%, 10% and 2%, respectively. The sensitivity of the HCS for anaemia ranged from 60% to 79% and specificity from 59% to 94%. The sensitivity of the HCS for severe anaemia ranged from 24% to 63% and the specificity from 97% to 100%. Through use of the HCS, the proportion of sick, anaemic children visiting peripheral health facilities diagnosed and treated for anaemia would increase from 3% to 65%.

CONCLUSIONS

In an area with high prevalence of anaemia among sick children, use of the HCS has the potential to significantly increase the proportion of sick, anaemic children who are diagnosed with anaemia and given appropriate treatment. Further evaluations of the effect of the use of the HCS on treatment practices at the health facility level are required.

Diagnostic accuracy comparison between clinical signs and hemoglobin color scale as screening methods in the diagnosis of anemia in children

OBJECTIVES: to compare the validity and reproducibility of clinical signs with the World Health Organization hemoglobin color scale. METHODS: Two hundred six children in the age range of 6-23 months, at the Instituto Materno Infantil Prof. Fernando Figueira, IMIP, were assessed. Two examiners evaluated the clinical signs and the hemoglobin color scale of each child at the different times. The hemoglobin value was used as a standard for validation. RESULTS: in more than 90% of cases the agreement between the values of the color scale and the laboratorial hemoglobin was <2 g/dL. Between the clinical signs the highest sensitivity level for diagnosing Hb<11 g/dL was presented by the hemoglobin color scale (75.7%). For moderate/severe anemia Hb<9g/dL the highest sensitivity was shown by combined palmar or conjunctival pallor (74.3%) and by the color scale (52.5%), according to the first and second observer, respectively. The highest specificity level for Hb<11 g/dL was presented by palmar pallor in comparison with the mother's palm and conjunctival pallor (100%). For Hb<9 g/dL the highest specificity was presented by the hemoglobin color scale (91.9%). CONCLUSIONS: this study suggests that moderate/severe anemia can be diagnosed either by clinical signs or by the color scale, while, in cases of mild anemia, the better diagnosis tool appears to be the color scale.

Haemoglobin colour scale for anaemia diagnosis where there is no laboratory: a systematic review

BACKGROUND

Anaemia is a major public health problem, in poor countries most of the cases are diagnosed clinically. This is inaccurate and the haemoglobin colour scale (HCS) has been developed as an inexpensive, simple alternative for assessing anaemia. Laboratory and community studies have assessed its diagnostic accuracy, but controversy over its validity and usefulness remains. We carried out a systematic review to identify and summarize studies, explain heterogeneity, and make recommendations for future research.

METHODS

We searched electronic databases (MEDLINE, EMBASE, CINAHL, and Science Citation Index), checked documents and references, and contacted experts. We included all the studies comparing HCS diagnostic accuracy with a reference standard. Both reviewers independently screened titles and abstracts, assessed studies for inclusion, appraised quality, and extracted data.

RESULTS

We included 14 studies, mostly from sub-Saharan Africa. Studies had heterogeneous populations, health care settings, anaemia prevalence, and findings. HCS sensitivity for detecting anaemia was high in most of the studies (75-97%); specificity was generally lower (41-98%). Sensitivity and specificity were higher for laboratory-based studies compared with more pragmatic 'real-life' studies, and the 'study setting' appeared to explain some of the heterogeneity. Five studies compared the HCS with clinical diagnosis; sensitivity was higher for the HCS in four studies, but specificity was often higher with clinical diagnosis. A few studies evaluated the HCS in situations where there was no laboratory.

CONCLUSIONS

The HCS may improve anaemia diagnosis where there is no laboratory, but there is a need for policy-relevant diagnostic research which is pragmatic, implementation-focused and assesses clinical outcomes. This requires a different approach and research skill-mix from efficacy studies.

Clinical use of WHO haemoglobin colour scale: validation and critique

AIM

The World Health Organisation (WHO) haemoglobin colour scale has been developed as a simple, inexpensive clinical device for diagnosing anaemia when laboratory based haemoglobinometry is not available. In an initial validation study at several health centres, scale readings were compared with measurements of haemoglobin by the laboratory. This showed the scale to have 90% sensitivity and 70% specificity in identifying whether anaemia was present or not. In addition, when present, the degree of anaemia was correctly classified in clinical terms as moderate, pronounced, or severe, with an overall sensitivity of 60% and specificity of 88%. Errors were mainly marginal--that is, between two adjacent categories--but there were also some major discrepancies, such as a blood with a haemoglobin of 6-7 g/dl being read as normal or vice versa. Because this would compromise the scale's reliability in practice, this study was undertaken to identify the cause of the discrepancies and to reassess the performance of the scale.

METHODS

Venous blood samples were collected into potassium EDTA from patients attending selected clinics at three South African hospitals with good laboratory facilities. A prototype of the device was used unsupervised by nursing staff, doctors, and phlebotomists, who were told to follow the printed instructions. The blood specimens were then immediately sent to the laboratory where haemoglobin was measured by standardised automated blood cell counters. Any discrepancies > 1 g/dl were recorded and the tests were repeated by the same operators under supervision of the investigators.

RESULTS

Almost all the errors that occurred resulted from the incorrect use of the device, namely: inadequate or excessive blood, reading the results too soon or too late (beyond the limit of two minutes), poor lighting, or holding the scale at the wrong angle. The accuracy improved dramatically when the tests were repeated under supervision and these faults were avoided: 95% of readings were within 1 g/dl of the reference measurements, and 97% within 1.5 g/dl. Anaemia screening showed 96% sensitivity and 86% specificity. Clinical judgement of pallor was frequently wrong, whereas the scale gave the correct diagnosis in more than 97% of cases.

CONCLUSION

The study confirmed the usefulness and reliability of the scale and its advantage over clinical signs for the diagnosis of anaemia, thus providing a clinically reliable near patient method in the absence of a laboratory. The instructions are easy to follow but must be strictly adhered to.