Variation In Haemoglobin Reference Ranges And Implications For Use Of Health Service Resource In The Republic Of Ireland And The UK

Variation in the lower and upper limits of haemoglobin (Hb) ranges will alter diagnosis and referral rates of anaemia or erythrocytosis. The haemoglobin ranges for adults in Irish laboratories were applied in the context of haemoglobin levels of a representative sample of Irish adults (SLAN). Between 2.8% and 8.5% of men would be diagnosed with anaemia in different laboratories for lower limit between 130-140g/L. For women, diagnosis of anaemia would range from 0.7% to 7.3% for the lower limit between 110-125g/L. Similar reference range variations occur in UK laboratories. A suggested “normal reference range” is extrapolated from the SLAN cohort. DOI : 10.14302/issn.2372-6601.jhor-13-352 Corresponding author: Jennifer Mary O’ Sullivan, Department of Haematology, Cork University Hospital, Wilton Road, Cork, jennifer.m.osullivan@gmail.com Running title: Variation in haemoglobin reference ranges and implications for use of health service resource in the Republic of Ireland and the UK


Short Communication
A diagnosis of anaemia is considered when the haemoglobin level is below the lower limit of the reference range used by a laboratory and erythrocytosis is diagnosed when the level exceeds the upper limit.
Variation in the level of the upper and lower limit will affect diagnosis of these conditions and referral rates.In Ireland, haemoglobin is tested for both men and women in 53 laboratories and for women alone in 5 laboratories.In adult men, the lower limit varied from 130-140g/L and the upper limit from 167-185g/L.In adult women, the lower limit varied from 110-125g/L and the upper limit from 148-165g/L.At least 14 different analysers were used across the laboratories.
Standard haematology textbooks were the confirmed source of reference ranges in at least 6 laboratories.
Haemoglobin variation was similar in the sample of UK laboratories; in men, a lower and upper limit varied from 130-135g/L and 166-180g/L respectively and in women, a lower and upper limit varied from 112-120g/L and 145-165g/L, respectively.
Biomnis laboratory analysed the SLAN data and its reference range was used as the "gold" standard using Sysmex XE 2100 analyser (135-172g/L in adult men, 113-152g/L in adult women).A "true normal" reference range was extrapolated from the SLAN data, excluding those diagnosed as iron deficient (based on a ferritin below the lower limit of normal) and those diagnosed with B12 and folate deficiency.For this range, there was a total 972, of which 437 were male and 535 were female.The range was calculated using the mean (153g/L for men, 140g/dL for women) and standard deviations (11g/L for men, 9g/L for women).The range would be 131-175g/L for men and 122-158g/L for women.
The data demonstrate that there is a wide variation in lower and upper haemoglobin limits in both Ireland and the UK, with an almost 20g/L difference at the upper limit in both genders.A variety of analysers are used in the laboratories and the sources of the reference ranges vary.The use of haematology textbooks in some laboratories in Ireland and the UK as the reference range source is concerning.For haemoglobin, normal values should ideally be derived from a representative sample of healthy persons in whom presence of nutrient deficiency has been excluded [2].
On applying the SLAN data to the variation of haemoglobin reference ranges, there was substantial variation in the proportion of the population that would Haemoglobin reference ranges were ascertained for adults in Irish laboratories and in a sample of UK laboratories.The variation in the limits of haemoglobin normal ranges were analysed in the context of findings on haemoglobin concentrations from a large, nationally representative sample of Irish adults.Haemoglobin reference ranges for adult men and women used in every laboratory in Ireland (n=53) and some in the UK (n=35) were obtained via phone contact, email correspondence or laboratory/hospital websites.Data were also obtained on the type of analyser used in each laboratory and on the source of the reference ranges.Haemoglobin levels were measured in a sample of 1,133 men and women aged ≥45 years, participants in the 2007 Irish National Survey of Lifestyle Attitudes and Nutrition (SLAN 2007)[1].

Table 1 :
Shows the variation in proportion of anaemia diagnoses depending on the lower limit of haemoglobin concentration.

Table 2
Shows the variation in proportion of erythrocytosis diagnoses made.