Background: Various medical conditions in pregnancy may be traced to suboptimal levels of serum calcium during pregnancy. Communities' derivation of normal serum calcium reference interval is imperative.
Objective: The objective was to determine the normal free (ionised) serum calcium reference interval among women of reproductive age in the federal capital territory (FCT) of Nigeria.
Materials and methods: This was a cross-sectional study of 240 women from six primary health-care facilities in Abuja, Nigeria. Their blood samples were collected in serum separator bottles. The outcome measure was the determination of the reference interval of free (ionised) serum calcium among the participants.
Results: The obtained normal reference interval of ionised serum calcium (iCa) was 0.88-1.4 mmol/L. The accompanying reference intervals for total protein and albumin were 5.7-9.4 mg/dl and 3.3-5.2 mg/dl, respectively.
Conclusion: The derived reference interval of iCa in this study was 0.88-1.4 mmol/L, while the total calcium range was 2.18-2.82 mmol/L. These intervals are recommended for use in the Nigerian FCT and its environs as it provides lower intervals compared to the operational values. There is a need for a national derived value as this may change the practice.
Keywords: Federal capital territory; reproductive age; serum calcium; women.