Immigrant health: laboratory reference ranges may differ from indigenous population’s with potential for misinterpretation  

Dear Sir,

Among several desirable facets, immigrants assist with technological advancement and have a net positive impact on the public purse1. However recent migrants tend not to have adequate knowledge about their new country’s social and health care system2. It is thus not surprising that recent immigrants tend to have poorer outcomes for the same disease compared to locals – when matched for disease severity and other characteristics, as previously reported in this journal3. Herein a case is presented of a recent immigrant to Ireland (10 months) to illustrate how interpreting laboratory results in immigrants can be nuanced.

A 32yearold male from Southern Africa presented to a primary care physician for a health check-up. His history was unremarkable except for a family history of type 2 diabetes mellitus. Physical examination was notable for an elevated blood pressure of 140/87 mm Hg, which was attributed to white coat hypertension; nevertheless his blood pressure is being followed up. Tests for major infectious conditions prevalent in Southern Africa, and routine clinical chemistry and haematology profiles were unremarkable except for a low mean corpuscular volume (MCV) of 79.3 fL (reference range [RR] 80 – 96 fL) and mean cell haemoglobin (MCH) of 26.6 pg (RR 27 – 33 pg). However these apparently abnormal values were normal when contemporary reference ranges from his Southern African country were used, MCV (RR 72.8 – 102.6 fL) and MCH (RR 22.9 – 33.5 pg)4.

This case highlights how there is risk of misinterpreting laboratory results with possibly adverse consequences (no or inappropriate treatment). It also illustrates how possible misinterpretation can easily be avoided by accessing robust publicly available laboratory data over the World Wide Web. Because Ireland’s population is increasingly becoming diverse and multicultural, this letter also serves to remind clinicians, laboratory personnel and other allied workers to be vigilant when caring for recent immigrants who are a vulnerable group3.

G Masukume
Department of Obstetrics and Gynaecology, University College Cork, Cork, Ireland.

Dr. Gwinyai Masukume, Irish Centre for Fetal and Neonatal Translational Research, (INFANT), Cork University Maternity Hospital, 5th Floor, Wilton, Cork, Ireland
Tel: +353 21 420 5031

1. OECD. Migration policy debates. 2014 Available: Accessed 20 April 2017.
2. Benza S, Liamputtong P. Becoming an ‘Amai': Meanings and experiences of motherhood amongst Zimbabwean women living in Melbourne, Australia. Midwifery. 2017;45:72-78. doi: 10.1016/j.midw.2016.12.011
3. Thabit H, Martin G, Brema I, Daly M, Walsh S, Mannion C, Nolan JJ. Immigrant patients with type 2 diabetes mellitus have poorer initial and on-going glycemic control than a matched population of Irish patients. Ir Med J. 2008;101:177-80.
4. Samaneka WP, Mandozana G, Tinago W, Nhando N, Mgodi NM, Bwakura-Dangarembizi MF, Munjoma MW, Gomo ZA, Chirenje ZM, Hakim JG. Adult Hematology and Clinical Chemistry Laboratory Reference Ranges in a Zimbabwean Population. PLoS One. 2016;11:e0165821. doi: 10.1371/journal.pone.0165821