WHO recommendation on the method for diagnosing anaemia in pregnancy

WHO recommendation on the method for diagnosing anaemia in pregnancy

 

Recommendation

Full blood count testing is the recommended method for diagnosing anaemia during pregnancy. In settings where full blood count testing is not available, onsite haemoglobin testing with a haemoglobinometer is recommended over the use of the haemoglobin colour scale as the method for diagnosing anaemia in pregnancy.

(Context-specific recommendation)

 

Publication history

First published: December 2016

Updated: No update planned

Assessed as up-to-date: December 2016

 

Remarks

  • The GDG agreed that the high recurrent costs of Hb testing with haemoglobinometers might reduce the feasibility of this method in some low-resource settings, in which case the WHO haemoglobin color scale method may be used.
  • Other low-technology on-site methods for detecting anaemia need development and/or investigation.
  • Context-specific recommendation refers to: recommended only in the context of rigorous research/ recommended only with targeted monitoring and evaluation/ recommended only in other specific contexts.

 

Background

Defined as a blood haemoglobin (Hb) concentration below 110 g/L, anaemia is the world’s second leading cause of disability, and one of the most serious global public health problems, with the global prevalence of anaemia among pregnant women at about 38% (1).

Clinical assessment (inspection of the conjunctiva for pallor) is a common method of detecting anaemia but has been shown to be quite inaccurate. In HICs, performing a full blood count, which quantifies the blood Hb level, is part of routine ANC (2). However, this and other available tests may be expensive, complex or impractical for use in rural or LMIC settings. A low-cost and reliable method of detecting anaemia is therefore needed for places with no or limited Access to laboratory facilities. WHO developed the haemoglobin colour scale, a low-cost method that is performed by placing a drop of undiluted blood on specially made chromatography paper and matching it against a range of colours representing different Hb values in 20 g/L increments (3). With haemoglobinometer tests, undiluted bloodis placed directly into a microcuvette, which is inserted into the haemoglobinometer (or photometer) to produce a reading (3)

 

Methods

The ANC recommendations are intended to inform the development of relevant health-care policies and clinical protocols. These recommendations were developed in accordance with the methods described in the WHO handbook for guideline development (4). In summary, the process included: identification of priority questions and outcomes, retrieval of evidence, assessment and synthesis of the evidence, formulation of recommendations, and planning for the implementation, dissemination, impact evaluation and updating of the guideline.

The quality of the scientific evidence underpinning the recommendations was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) (5) and Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual)  (6) approaches, for quantitative and qualitative evidence, respectively. Up-to-date systematic reviews were used to prepare evidence profiles for priority questions. The DECIDE (Developing and Evaluating Communication Strategies to support Informed Decisions and Practice based on Evidence) (7) framework, an evidence-to-decision tool that includes intervention effects, values, resources, equity, acceptability and feasibility criteria, was used to guide the formulation and approval of recommendations by the Guideline Development Group (GDG) – an international group of experts assembled for the purpose of developing this guideline – at three Technical Consultations between October 2015 and March 2016.

To ensure that each recommendation is correctly understood and applied in practice, the context of all context-specific recommendations is clearly stated within each recommendation, and the contributing experts provided additional remarks where needed.

In accordance with WHO guideline development standards, these recommendations will be reviewed and updated following the identification of new evidence, with major reviews and updates at least every five years.

Further information on procedures for developing this recommendation are available here.

 

Recommendation question

For this recommendation, we aimed to answer the following question:

  • For pregnant women (P), what is the diagnostic value of on-site tests for assessing blood haemoglobin concentration (I) compared with the reference standard (full blood count) (C) to detect maternal anaemia (O)? 

 

Evidence summary

The evidence was derived from a test accuracy review conducted to support the ANC guideline (2). Only one study (671 women) contributed data (8). The study, conducted in Malawi, assessed the test accuracy of on-site Hb testing with a haemoglobinometer (HemoCue®) and the HCS method in comparison to a full blood count test performed by an electronic counter (Coulter counter), the reference standard.

Moderate-certainty evidence shows that the sensitivity and specificity of the haemoglobinometer test in detecting anaemia (Hb < 110 g/L) are approximately 0.85 (95% CI: 0.79–0.90) and 0.80 (95% CI: 0.76–0.83), respectively, while the sensitivity and specificity of the HCS method are lower at approximately 0.75 (95% CI: 0.71–0.80) and 0.47 (95% CI: 0.41–0.53), respectively. For severe anaemia (defined in the study as Hb < 60 g/L), moderate-certainty evidence shows that the sensitivity and specificity of the haemoglobinometer test are approximately 0.83 (95% CI: 0.44–0.97) and 0.99 (95% CI: 0.98–1.00), respectively, while for the HCS method they are approximately 0.50 (95% CI: 0.15–0.85) and 0.98 (95% CI: 0.97–0.99), respectively.The technique included the use of both lower segment compression with one hand through the abdominal wall and bimanual lower segment and fundal compression through the abdominal wall.(9) The authors reported a decrease in the amount of blood loss in the group in which manual lower segment compression was used together with conventional management. Only one case report was found describing the bimanual abdominal/intravaginal technique.(10)

The main limitation of the evidence is the low number of women identified with severe anaemia, which affects the precision of the estimates. However, the evidence suggests that the haemoglobinometer test is probably more accurate than the HCS method. As there are no direct comparisons in test accuracy studies and, as confidence intervals for sensitivity and specificity of the two methods overlap, there is some uncertainty about the relative accuracy of these tests. The review also evaluated the test accuracy of clinical assessment (4 studies, 1853 women), giving a sensitivity for clinical assessment of 0.64 (95% CI: 22–94) and a specificity of 0.63 (95% CI: 23–91) for detecting anaemia (Hb < 110 g/L). Thus, the HCS method might be more sensitive but less specific than clinical assessment. In settings where iron supplementation is routinely used by pregnant women, the consequence of missing women with severe anaemia is more serious than that of missing women with mild or moderate anaemia, as women with severe anaemia usually require additional treatment. Therefore, the accuracy of on-site Hb tests to detect severe anaemia in pregnancy is probably more important than the ability to detect Hb below 110 g/L. A study of various Hb testing methods in Malawi found the haemoglobinometer method to be the most user-friendly method.

Further information on evidence supporting this recommendation are available here.

 

Implementation considerations

  • The successful introduction of evidence-based policies related to antenatal care into national programmes and health care services depends on well-planned and participatory consensus-driven processes of adaptation and implementation. These processes may include the development or revision of national guidelines or protocols based on this recommendation.
  • The recommendation should be adapted into locally-appropriate documents and tools that are able to meet the specific needs of each country and health service. Modifications to the recommendation, where necessary, should be justified in an explicit and transparent manner.
  • An enabling environment should be created for the use of this recommendation, including changes in the behaviour of health care practitioners to enable the use of evidence-based practices.
  • Local professional societies may play important roles in this process and an all-inclusive and participatory process should be encouraged.
  • Antenatal care models with a minimum of eight contacts are recommended to reduce perinatal mortality and improve women’s experience of care. Taking this as a foundation, the GDG reviewed how ANC should be delivered in terms of both the timing and content of each of the ANC contacts, and arrived at a new model – the 2016 WHO ANC model – which replaces the previous four-visit focused ANC (FANC) model. For the purpose of developing this new ANC model, the ANC recommendations were mapped to the eight contacts based on the evidence supporting each recommendation and the optimal timing of delivery of the recommended interventions to achieve maximal impact.

 

Additional considerations

  • Any health-care provider can perform both the haemoglobinometer and HCS methods after minimal training. Both methods require needles for finger pricks, cotton balls, gloves and Sterets® skin cleansing swabs; however, the higher costs associated with haemoglobinometer tests are mainly due to supplies (cuvettes and controls), equipment costs and maintenance.
  • Anaemia increases perinatal risks for mothers and newborns and contributes to preventable mortality. Accurate, low-cost, simple-to-use tests to detect anaemia might help to address health inequalities by improving the detection and subsequent management of women with anaemia, particularly severe anaemia, in low-resource settings.
  • Qualitative evidence from a variety of settings indicates that women generally appreciate clinical tests that support their well-being during pregnancy (moderate confidence in the evidence) (22). However, evidence from LMICs indicates that where there are likely to be additional costs associated with tests, or where the recommended interventions areunavailable because of resource constraints, women may be less likely to engage with ANC services (high confidence in the evidence).
  • Qualitative evidence from providers in various LMICs indicates that a lack of resources, both in terms of the availability of the diagnostic equipment and potential treatments, as well as the lack of suitably trained staff to deliver the service, may limit implementation of recommended interventions (high confidence in the evidence)

 

Research implications

The GDG identified this research priority related to this recommendation

  • Can better and more cost–effective on-site tests to diagnose anaemia be developed?

 

Related links

WHO recommendations on antenatal care for a positive pregnancy experience

(2016) - full document and evidence tables

Managing Complications in Pregnancy and Childbirth: A guide for midwives and doctors

Pregnancy, Childbirth, Postpartum and Newborn Care: A guide for essential practice

WHO Programmes: Sexual and Reproductive health

WHO Health Topics: Anemia

 

 

References

  1. The global prevalence of anaemia in 2011. Geneva: World Health Organization; 2015 (http://apps.who.int/iris/bitstream/10665/177094/1/9789241564960_eng.pdf,... 29 September 2016).
  2. Sobhy S, Rogozinska E, Khan KS. Accuracy of onsite tests to detect anaemia in antenatal care: a systematic review. BJOG. 2016 (in press).
  3. Medina Lara A, Mundy C, Kandulu J,Chisuwo L, Bates I. Evaluation and costs of different haemoglobin methods for use in district hospitals in Malawi. J Clin Pathol. 2005;58(1):56–60.
  4. WHO handbook for guideline development, 2nd edition. Geneva: World Health Organization; 2014 (http://www.who.int/kms/handbook_2nd_ ed.pdf, accessed 6 October 2016).
  5. GRADE [website]. The GRADE Working Group; 2016 (http://gradeworkinggroup.org/, accessed 27 October 2016).
  6. GRADE-CERQual [website]. The GRADECERQual Project Group; 2016 (https://cerqual. org/, accessed 27 October 2016). 17. DECIDE [website].
  7. The DECIDE Project; 2016 (http://www.decide-collaboration.eu/, accessed 27 October 2016).
  8. van den Broek NR, Ntonya C, Mhango E, White SA. Diagnosing anaemia in pregnancy in rural clinics: assessing the potential of the Haemoglobin Colour Scale. Bull World Health Organ. 1999;77(1):15–21.
  9. Maternal mortality. Fact sheet No. 348; Geneva: World Health Organization; 2014 (http://www.who.int/mediacentre/factsheets/fs348/en/index.html, accessed 22 June 2014).
  10. Maternal mortality. Fact sheet No. 348; Geneva: World Health Organization; 2014 (http://www.who.int/mediacentre/factsheets/fs348/en/index.html, accessed 22 June 2014).

 

Citation: WHO Reproductive Health Library. WHO recommendation on the method for diagnosing anaemia in pregnancy (December 2016). The WHO Reproductive Health Library; Geneva: World Health Organization.