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Introduction: Macroprolactinaemia is defined as hyperprolactinaemia due to excess macroprolactin in the presence of normal monomeric prolactin. Failure to identify macroprolactinaemia may result in patients being subjected to unnecessary investigations and inappropriate treatment for hyperprolactinaemia. In our centre, screening for macroprolactinaemia is currently performed at the request of the treating physician. The study thus aimed to determine the frequency of macroprolactinaemia in samples with serum prolactin ≥700 mIU/L in Hospital Tengku Ampuan Rahimah (HTAR) and to determine the presence of true hyperprolactinaemia in these cases. Methods: A cross-sectional study among hyperprolactinaemic subjects in HTAR, using serum specimens received by the laboratory for measurement of prolactin between October 2018 and September 2019. Samples with prolactin ≥700 mIU/L were screened for macroprolactinaemia using the polyethylene glycol (PEG) precipitation technique. Macroprolactinaemia was present when the percentage recovery of prolactin post-PEG was <40%. Assay-specific post-PEG monomeric prolactin levels were also reported, with levels above the upper limit of reference intervals indicated the presence of true hyperprolactinaemia. Results: A total of 101 samples were subjected to PEG precipitation. Macroprolactinaemia was found in four (4%) samples, whilst eight (7.9%) were categorised as indeterminate (percentage recovery of 40-60%). The remaining 89 (88.1%) samples had a percentage recovery >60%, hence considered negative for macroprolactinaemia. All four samples with macroprolactinaemia also had raised monomeric prolactin levels indicating the co-existence of macroprolactinaemia in subjects with true hyperprolactinaemia. Similarly, in the indeterminate group, all eight had raised monomeric prolactin levels. Conclusion: In one-year period in HTAR, macroprolactinaemia was detected in 4% of subjects with prolactin ≥700 mIU/L, all of whom also had raised monome

Adrenal hypoplasia congenita (AHC) is a rare inherited condition due to the failure of the adult zone of the adrenal cortex to develop despite normal development of its foetal counterpart. Affected patients are usually asymptomatic at birth but will present with clinical features of acute adrenal insufficiency during early infancy. It is clinically indistinguishable from the more common congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. Here, we report a case of a one-month-old male infant with primary adrenal insufficiency (PAI) whose initial laboratory investigations revealed hyponatraemia and severe hyperkalaemia. The early onset of PAI with the absence of ambiguous genitalia and low baseline and adrenocorticotropic-stimulated 17-hydroxyprogesterone and undetectable dehydroepiandrosterone sulfate levels, suggest the possibility of AHC in this infant. Genetic analysis is crucial to confirm the diagnosis of this condition and to differentiate from CAH as their prognoses and management differ.

Introduction: Total calcium concentration is widely used to assess body calcium status although limited by many confounding factors. Thus, this study aimed to derive and internally validate an albumin-adjusted calcium equation for a selected Malaysian population. Method: This cross-sectional study involved 1011 adults at an emergency department of a tertiary hospital. Patients who had total calcium, ionised calcium and albumin measurements taken simultaneously were included. Derivation of the albumin-adjusted calcium equation was based on the adjustment equation obtained from the Association for Clinical Biochemistry and Laboratory Medicine 2015 position paper. Additionally, the equation was internally validated and compared with ionised calcium (gold standard) and the conventional Payne’s equation. Results: The newly derived equation = total calcium + 0.017 (41.35 – albumin). Internal validation exhibited the amount of shrinkage of 0.049. It tends to overestimate the adjusted calcium by a mean difference of 0.029 mmol/L compared to Payne’s equation. The comparison between Payne’s equation and the new equation with ionised calcium reclassified 402 and 486 patients, respectively into different calcium status. When both equations were compared, calcium status classification significantly differed in all and hypoalbuminaemic subjects by 90 and 16 patients, respectively. Conclusion: Locally derived albumin-adjusted calcium equation differed statistically in calcium status classification when compared to the Payne’s equation. However, to confirm this significance, the result must be compared to ionised calcium under strict, controlled preanalytical conditions. In terms of clinical significance, there was no difference in classification of calcium status between Payne’s and the new equation at medical decision limits.