gentleman
Anaemia is a condition
in which the number of red blood cells (and
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conquently their oxygen-carrying capacity) is insufficient to meet the body’s physiologic needs. Specific physiologic needs vary with a person’s age, gender, residential elevation above a level (altitude), smoking behaviour, and different stages of pregnancy. Iron deficiency is thought to be the most common cau of anaemia globally, but other nutritional deficiencies (including folate, vitamin B 12 and vitamin A), acute and chronic inflammation, parasitic infections, and inherited or acquired disorders that affect haemoglobin synthesis, red blood cell production or red blood cell survival, can all cau anaemia. Haemoglobin concentration alone cannot be ud to diagno iron deficiency. However, the concentration of haemoglobin should be measured, even though not all anaemia is caud by iron deficiency. The prevalence of anaemia is an important health indicator and when it is ud with other measurements of iron status the haemoglobin concentration can provide information about the verity of iron deficiency (1).
Inside
Background
Scope and purpo
This document aims to provide urs of the Vitamin and Mineral Nutrition Information System (VMNIS) with information about the u of haemoglobin concentration for diagnosing anaemia. It is a compilation of current World Health Organization (WHO) recommendations on the topic and summarizes the cut-offs for defining anaemia and its verity at the population level, as well as the chronology of their establishment.
The u of the cut-off points derived from the referenced publications permits the identification of populations at greatest risk of anaemia and priority areas for action, especially when resources are limited. They also facilitate the monitoring and asssment of progress towards international goals of preventing and controlling iron deficiency and further provide the basis for advocacy for the prevention of anaemia.
VMNIS | Vitamin and Mineral Nutrition Information System
WHO/NMH/NHD/MNM/11.1
Background
1
Description of
technical consultation
2游戏动漫学院
Recommendations
3
Summary development
Acknowledgements
5
Plans for update
5
References
6
4
Scope and purpo
1
Description of technical consultation
This document compiles current WHO guidelines from five documents:
Nutritional anaemias (2), is a report of a WHO Scientific Group that consisted of an international gro
高中英语教案up of experts convened in Geneva, Switzerland from 13-17 March 1967. The consultation was called three years after the start of a worldwide multi-country collaborative study in India, Israel, Mexico, Poland, South Africa, the United Kingdom, the United States of America, and Venezuela. The study investigated iron metabolism in pregnancy as well as the role of hookworm in anaemia during pregnancy, and further tested the procedures for examining blood and rum. The 1967 consultation reviewed overall progress of the studies and also discusd nutritional requirements of iron, folate, and vitamin B12.
Preventing and controlling anaemia through primary health care (3) was published after a May 1987 meeting of the International Nutritional Anaemia Consultative Group (INACG) in Quito, Ecuador. This publication aims to help health administrators and programme managers to develop and implement suitable strategies for preventing and controlling iron deficiency anaemia. It also considers some of the practical aspects of integrating primary care at various levels of organization learnt from the JNSP (WHO/UNICEF Joint Nutrition Support Programme), which was active in 18 countries at that time.
The management of nutrition in major emergencies (4) was published by WHO in respon to the World Declaration and Plan for Action in Nutrition (5) that urged governments to provide sustainable 广州汽修学校
assistance to refugees, displaced and war-affected populations where high rates of malnutrition and micronutrient deficiencies occur.
Iron deficiency anaemia: asssment, prevention and control, a guide for programme managers (6), a document published in 2001, is mainly bad on a consultation organized by WHO, UNICEF, and the United Nations University (UNU) held in Geneva, Switzerland, 6-10 December 1993. The purpo of this consultation was to provide scientists and national authorities a timely and authoritative review of iron deficiency anaemia, and also to help managers of national micronutrient malnutrition prevention and control programmes to identify effective measures for fighting iron deficiency anaemia. The conclusions of the consultation were complemented with additional scientific literature that appeared before 2000.
Asssing the iron status of populations (1) is the report of a joint WHO and US Centers for Dia Control and Prevention (CDC) Technical Consultation held in Geneva, Switzerland, 6-8 April 2004, with the participation of 34 experts. With the ultimate goal of planning effective interventions to combat both iron deficiency and anaemia, the objectives of the Consultation were to review the indicators currently available to asss iron status, to lect the best indicators for asssing the iron status of populations, to lect the best indicators to evaluate the impact of interventions to control ir
on deficiency in populations, and to identify priorities for rearch related to asssing the iron status of populations. This Consultation was preceded by a short WHO/CDC working group meeting held in January 2004 to review the literature on indicators of iron status and to lect indicators for discussion. In April 2004, the Consultation was provided with literature reviews on indicators of iron status, including red blood cell (RBC) parameters, ferritin, free erythrocyte protoporphyrin, rum and plasma iron, total iron binding capacity, transferrin saturation and rum transferrin receptor as well as a review on the interpretation of indicators of iron status during an acute pha respon. The four reviews are available in the cond edition, published in 2007.
Table 1
Haemoglobin levels to diagno anaemia at a level (g/l)±
The anaemia cut-offs prented in Table 1 were published in 1968 by a WHO study group on nutritional anaemias (2), while the cut-offs defining mild, moderate and vere anaemia were first prented in the 1989 guide Preventing and controlling anaemia through primary health care (3) an
d then modified for pregnant women, non-pregnant women, and children less than five years of age in The management of nutrition in major emergencies (4). The overall anaemia cut-offs have been unchanged since 1968, with the exception that the original age group of children 5-14 years of age was split, and a cut-off of 5 g/l lower was applied to children 5-11 years of age to reflect findings among non-iron deficient children in the USA (6). Although the cut-offs were first published in the late 1960s, they have been included in numerous subquent WHO publications (3,4,6) and were additionally validated by findings among participants in the Second National Health and Nutrition Examination Survey (NHANES II) who were unlikely to have iron deficiency bad on a number of additional biochemical tests (7).
The haemoglobin cut-off of 110 g/l for pregnant women was first prented in the 1968 report along with results of the five studies mentioned previously. In healthy, iron-sufficient women, haemoglobin concentrations change dramatically during
Recommendations
Population
Anaemia*
Non -Anaemia*
Mild a Moderate Severe Children 6 - 59 months of age 110 or higher 100-109 70-99 lower than 70 Children 5 - 11 years of age 115 or higher 110-114 80-109 lower than 80 Children 12 - 14 years of age 120 or higher 110-119 80-109 lower than 80 Non-pregnant women (15 years of age and above) 120 or higher 110-119 80-109 lower than 80 Pregnant women
110 or higher 100-109 70-99 lower than 70 Men (15 years of age and above)
130 or higher
110-129
80-109
lower than 80
pregnancy to accommodate the increasing maternal
blood volume and the iron needs of the fetus (3). Concentrations decline during the first trimester, reaching their lowest point in the cond trimester, and begin to ri again in the third trimester. Currently, there are no WHO recommendations on the u of different haemoglobin cut-off points for anaemia by trimester, but it is recognized that during the cond trimester of pregnancy, haemoglobin concentrations diminish approximately 5 g/l.
Residential elevation above a level and smoking are known to increa haemoglobin concentrations (6). Conquently, the prevalence of anaemia may be underestimated in persons residing at high altitudes and among smokers if the standard anaemia cut-offs are applied. Table 2 prents the recommended adjustments to be made to the measured haemoglobin concentration among persons living at altitudes higher than 1000 metres above a level, and Table 3 prents the adjustments for smokers. The adjustments must be made to the measured haemoglobin concentration for the anaemia cut-offs prented in Table 1 to be valid. Elevation adjustments are derived using data from the US Centers for Dia Control and Prevention’s (CDC) Pediatric Nutrition Surveillance System in children living in mountainous states, while the smoking adjustments are derived from NHANES II data. Both黄色文学>insurgent
± Adapted from references 5 and 6 * Haemoglobin in grams per litre
a "Mild" is a misnomer: iron deficiency is already advanced by the time anaemia is detected. The deficiency has conquences even when no anaemia is clinically apparent.
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Table 2
Altitude adjustments to measured haemoglobin concentrations
Altitude
(metres above a level)
Measured haemoglobin adjustment (g/l)
< 1000 0 1000 -2 1500 -5 2000 -8 2500 -13 3000 -19 3500 -27 4000 -35 4500
-45
ucdSummary development
The main bibliographic sources of this summary were five WHO publications (1-4,6) relead between 1968 and 2005. It was considered that each of them provided inputs that helped to build the knowledge in this area. Briefly, haemoglobin cut-offs were first prented in the 1968 document (2) and were bad on four published references (8-11) and one t of unpublished obrvations. Definitions for mild, moderate, and vere anaemia were first published in 1989 (3) and slightly modified in a subquent publication on nutrition in emergencies (4), which also propos a classification to determine the public health significance of anaemia in populations. Finally, the 2001 guide for managers split the age group for children 5-14 years of age and applied a new, lower haemoglobin cut-off for children 5-11 years of age bad on NHANES II data. The 2001 document additionally provided haemoglobin adjustments for altitude and smoking.
adjustments are additive, i.e. smokers living at higher altitudes would have two adjustments made. In addition to elevation and smoking, it has been suggested that there are small differences in the distributions of haemoglobin values among different ethnic groups (6), however, the data is still scarce and the u of standard cut-offs is recommended
Both the method of haemoglobin measurement and blood sample source (capillary versus venous blood) can affect the measured haemoglobin concentration. The cyanmethemoglobin and the Hemo
Cue® system are the methods generally recommended for u in surveys to determine the population prevalence of anaemia (6). In the cyanmethemoglobin method, a fixed quantity of blood is diluted with a reagent and haemoglobin concentration is determined after a fixed time interval in an accurate, well calibrated photometer. The cyanmethemoglobin measurement is the reference laboratory method for the quantitative determination of haemoglobin and is ud for comparison and standardization of other methods (6). The HemoCue ® system is bad on the cyanmethemoglobin method and has been shown to be stable and durable in field ttings. The source of the blood sample should also be considered when asssing haemoglobin concentrations. Some studies suggest that haemoglobin values measured in capillary samples are higher than tho measured in venous samples, potentially leading to fal-negative results (6).
The haemoglobin cut-offs prented in Table 1 are ud to diagno anaemia in individuals in a screening or clinical tting, but the public health significance of anaemia in a population can then be determined by applying the criteria shown in Table 4.
Smoking status Measured haemoglobin
adjustment (g/l)
Non-smoker 0 Smoker (all) -0.3 ½ -1 packet/day -0.3 1-2 packets/day -0.5 ≥ 2 packets/day
-0.7
取代英语Table 3
Adjustments to measured haemoglobin concentrations for smokers
Table 4
Classification of public health significance of
anaemia in populations on the basis of prevalence estimated from blood levels of haemoglobin
Category of public health significance
Prevalence of anaemia
(%)
Severe 40 or higher Moderate 20.0 – 39.9 Mild 5.0 – 19.9 Normal
4.9 or lower
Plans for updating this summary
The WHO Micronutrients Unit, Department of Nutrition for Health and Development, is responsible for reviewing this document and if needed will update it by 2014, following the newly adopted WHO Handbook for guideline development (12) procedures.
Acknowledgements
This summary was coordinated by Dr Luz Maria de Regil with technical input from Dr Juan Pablo Pena-Rosas, Dr Sarah Cusick and Dr Sean Lynch.
WHO wishes to thank the Government of Luxembourg for their financial support.
Suggested citation
WHO. Haemoglobin concentrations for the diagnosis of anaemia and asssment of verity. Vitamin and Mineral Nutrition Information System. Geneva, World Health Organization, 2011 (WHO/NMH/NHD/MNM/11.1) (www.who.int/vmnis/indicators/haemoglobin.pdf , accesd [date]).
FOR FURTHER INFORMATION PLEASE CONTACT
Department of Nutrition for Health and Development (NHD) World Health Organization
20, Avenue Appia, 1211 Geneva, Switzerland Email: micronutrients@who.int
WHO home page: www.who.int © World Health Organization 2011
