Serum ferritin thresholds for the diagnosis of iron deficiency in pregnancy: a systematic review

Abstract

SUMMARYThe aim of this review was to understand the landscape of serum ferritin in diagnosing iron deficiency in the aetiology of anaemia in pregnancy. Iron deficiency in pregnancy is a major public health problem leading to the development of anaemia. Reducing the global prevalence of anaemia in women of reproductive age is a 2025 global nutrition target. Bone marrow aspiration is the gold standard test for iron deficiency but requires an invasive procedure; therefore, serum ferritin is the most clinically useful test. We undertook a systematic search of electronic databases and trial registers from inception to January 2016. Studies of iron or micronutrient supplementation in pregnancy with pre‐defined serum ferritin thresholds were included. Two independent reviewers selected studies, extracted data and assessed quality. There were 76 relevant studies mainly of observational study design (57%). The most commonly used thresholds of serum ferritin for the diagnosis of iron deficiency were <12 and <15 ng mL−1 (68%). Most primary studies provided no justification for the choice of serum ferritin threshold used, but 25 studies (33%) used thresholds defined by expert consensus in a guideline development process. There were five studies (7%) using a serum ferritin threshold defining iron deficiency derived from primary studies of bone marrow aspiration. Unified international thresholds of iron deficiency for women throughout pregnancy are required for accurate assessments of the global disease burden and for evaluating effectiveness of interventions addressing this problem.

UK guidelines on the management of iron deficiency in pregnancy

“…Research on pregnancy‐specific cut‐offs of serum ferritin are lacking (Roy & Pavord, ) and there is ongoing debate as to which serum ferritin level to use as threshold to diagnose iron deficiency (Garcia‐Casal et al , ). In the UK, the majority of clinicians are familiar with using a serum ferritin level <30 μg/l (Daru et al , ; Pavord et al , ). It may be appropriate to use a higher cut‐off, but as of yet there are no data to support this in pregnancy and the guideline group encourage continued use of a serum ferritin level <30 μg/l until good quality evidence suggesting another cut‐off emerges.…”

Iron Deficiency and Iron Deficiency Anemia: Implications and Impact in Pregnancy, Fetal Development, and Early Childhood Parameters

“…A number of studies suggest that it is the most effective single test for ID screening in pregnancy [45,46]. However, there is disagreement as to what constitutes a serum ferritin concentration diagnostic of ID in women [47,48]. This reflects the high frequency of asymptomatic ID among healthy women from whom population-based laboratory values are derived.…”

Reference intervals established using indirect method for serum ferritin assayed on Abbott Architect i2000SR analyzer in Chinese adults

“…Under normal circumstances, the amount of ferritin synthesized and secreted into the serum is proportional to the amount of cellular ferritin produced in the internal iron storage pathway, so that SF concentration is usually related to the quantity of body iron stores. Clinically, SF has been reported to link with iron‐deficiency anemia or a risk of iron overload . For these reasons, SF is widely used as a surrogate marker of iron stores.…”

“…Clinically, SF has been reported to link with irondeficiency anemia or a risk of iron overload. 6,7 For these reasons, SF is widely used as a surrogate marker of iron stores. In addition to this, SF has been found to be elevated in patient with inflammation, liver disease, and malignancy.…”