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.

Pregnancy- and lactation-related folate deficiency in South Africa--a case for folate food fortification.

OBJECTIVE: Characterisation of patients presenting with megaloblastic anaemia according to clinical, sociological, haematological and aetiological aspects of their disease, and use of these findings to increase awareness among clinicians and to make recommendations regarding changes in national health policy. METHODS: This study included 104 patients presenting with megaloblastic anaemia to a large referral hospital over a 1-year period. Data were collected and analysed in terms of age, gender, parity, gravidity, duration of lactation, socio-economic status, geographical origins, diet, previous haematinic treatment, clinical presentation and haematological measurements. RESULTS: The most common cause of megaloblastic anaemia was pernicious anaemia or probable pernicious anaemia (50%), followed by pregnancy- and lactation-related folate deficiency (32%); of these patients, the majority (28) presented postpartum while lactating; 5 patients were in the immediate puerperal period of 6 weeks, and a further 16 were seen during the first year and 7 during the second year following delivery. Only 4 patients were pregnant, and it is noteworthy that 2 of these were still lactating at 34 weeks' gestation. CONCLUSION: Pregnancy- and lactation-related folate deficiency up to 2 years after delivery remains a common cause of megaloblastic anaemia in South Africa. Certain communities in rural South Africa have recently been shown to have high incidences of both neural tube defects and folate deficiency. The fortification of a staple food (e.g. maize or flour) with folic acid is feasible, inexpensive, safe and likely to be beneficial. This practice should reduce the prevalences of megaloblastic anaemia in fertile women, neural tube defects, other congenital abnormalities, intra-uterine growth retardation, prematurity and possibly cardiovascular disease. There is urgent need for a national policy in this regard.

The value of the intrinsic factor antibody test in diagnosing pernicious anaemia.

OBJECTIVE: Assessment of the usefulness of the intrinsic factor antibody (IF Ab) test in comparison to the Schilling test in diagnosing pernicious anaemia (PA) in patients with vitamin B12 deficiency. DESIGN: This study was designed to compare the If Ab test to the Schilling test using results obtained of patients presenting with megaloblastic anaemia and low serum vitamin B12 levels to a large referral hospital. SETTING: The Chris Hani Baragwanath Hospital, Soweto, Gauteng, South Africa. SUBJECTS: Results from 77 patients with megaloblastic anaemia, low serum vitamin B12 levels and with both Schilling and IF Ab test results available were included. MAIN OUTCOME MEASURES: The sensitivity and specificity of the IF Ab test was compared to the Schilling test with regard to making a diagnosis of PA in patients presenting with megaloblastic anaemia and low serum vitamin B12 levels. RESULTS: Relevant statistical analysis showed that in the correct clinical setting, a confident diagnosis of PA could be made without Schilling tests in patients with megaloblastic anaemia, vitamin B12 deficiency and positive IF Ab tests. In a small proportion of patients in whom the IF Ab is negative, Schilling tests still need to be performed. CONCLUSION: With the increased concern over rising medical costs and where limited facilities are available, the IF Ab, in the correct clinical setting, is a cost effective and reliable test for diagnosis of PA.

Evaluation of DNA analysis for evidence of apoptosis in megaloblastic anaemia.

This study involved DNA analysis of bone marrow cells of 15 patients with megaloblastic anaemia. The diagnosis was based on the morphological changes seen in the bone marrow, associated with either a low red cell folate or serum vitamin B12 level and an adequate response to appropriate therapy as confirmation of the diagnosis. Flow cytometric DNA analysis showed an increase in the S and G2 phases of the cell cycle, but conventional agarose gel electrophoretic DNA analysis did not confirm the characteristic 'ladder pattern' which might have been expected in classic apoptosis. In addition, cells showing morphological changes suggestive of apoptosis, such as nuclear condensation and fragmentation, did not show evidence of DNA fragmentation using the ApopTag in situ digoxigenin nucleotide labelled, peroxidase detection system. Further studies using annexin V flow cytometric analysis and pulsed field gel electrophoresis were also unable to detect evidence of apoptosis as a significant cause of cell death in megaloblastic anaemia.