Diagnostic Tests

1. Overview: What this test reveals and why it is important Hepcidin is a peptide hormone produced primarily by the liver that serves as the master regulator of systemic iron homeostasis. Discovered in 2001, it has revolutionised our understanding of iron metabolism and its disorders . Hepcidin exerts its regulatory function by controlling the only known cellular iron exporter, ferroportin, which is located on the membrane of macrophages, hepatocytes, and the basolateral surf

Ferroportin (also known as SLC40A1, FPN1, or IREG1) is not a routine clinical blood test but rather a protein—the only known cellular exporter of elemental iron in humans . Understanding ferroportin is essential for interpreting iron studies (serum iron, ferritin, transferrin saturation) and diagnosing disorders of iron overload or deficiency. Ferroportin is a transmembrane protein expressed on the surface of cells that export iron into the bloodstream . Its primary locations

Quick Overview: Ceruloplasmin is a copper-containing blood protein made mainly in the liver. It carries most circulating copper and helps convert ferrous iron to ferric iron, which supports transferrin binding and normal iron transport. Because of this, the ceruloplasmin blood test can offer clues about copper metabolism, iron handling, liver function, and inflammatory states. Beyond iron homeostasis, ceruloplasmin also has antioxidant properties (scavenging superoxide radica

1. Overview: What this test reveals and why it is important Lithium is a monovalent cation and the lightest alkali metal, used for over seven decades as the gold standard mood stabiliser in psychiatry. It remains the most effective long-term treatment for bipolar disorder, significantly reducing the risk of both manic and depressive episodes, and is the only psychotropic medication consistently shown to reduce suicide mortality in mood disorders. It is also used as augmentati

1. Overview: What this test reveals and why it is important Parathyroid hormone (PTH) is an 84-amino acid polypeptide hormone secreted by the four parathyroid glands, which are located posterior to the thyroid gland in the neck. PTH is the primary regulator of calcium and phosphate homeostasis, acting directly on bone and kidney and indirectly on the intestine to maintain extracellular calcium concentration within a narrow physiological range. The secretion of PTH is tightly

1. Overview: What this test reveals and why it is important Iodine is an essential trace element and a critical component of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). These hormones regulate virtually every aspect of human metabolism, including basal metabolic rate, protein synthesis, enzyme activity, and neurological development. The human body contains approximately 15–20 mg of iodine, more than 70% of which is concentrated in the thyroid gland. Iodine

1. Overview: What this test reveals and why it is important Calcium is the most abundant mineral in the human body, with 99% stored in bones and teeth as hydroxyapatite, providing structural integrity. The remaining 1% in blood and soft tissues is tightly regulated because it is essential for: · Neuromuscular function: Nerve impulse transmission, muscle contraction (including cardiac muscle) · Blood coagulation: Cofactor for multiple clotting factors · Enzyme regulation: Cofa

1. Overview: What this test reveals and why it is important Magnesium is the fourth most abundant cation in the body and the second most abundant intracellular cation after potassium. It is a critical cofactor for over 300 enzymatic reactions, including: · Energy production: ATP metabolism requires magnesium‑ATP complexes. · Protein synthesis: Ribosomal function. · Nucleic acid synthesis and repair: DNA and RNA polymerases. · Neuromuscular excitability: Regulates ion channels

1. Overview: What this test reveals and why it is important Selenium is an essential trace mineral that plays a critical role in human health as a component of selenoproteins, including glutathione peroxidases, thioredoxin reductases, and iodothyronine deiodinases. These enzymes are fundamental to antioxidant defence, redox signalling, thyroid hormone metabolism, immune function, and reproduction. Measuring blood selenium levels provides insight into nutritional status and he

1. Overview: What this test reveals and why it is important Copper is an essential trace element that serves as a cofactor for numerous enzymes (cuproenzymes) critical for: · Iron metabolism: Ceruloplasmin (ferroxidase) oxidises ferrous iron to ferric iron, enabling iron binding to transferrin and preventing iron deficiency. · Neurotransmitter synthesis: Dopamine beta-hydroxylase converts dopamine to norepinephrine. · Antioxidant defence: Superoxide dismutase (SOD, copper‑zin

1. Overview: What this test reveals and why it is important Insulin is a peptide hormone produced by the beta cells of the pancreatic islets. It is the master regulator of glucose homeostasis, facilitating cellular glucose uptake, promoting glycogen synthesis in liver and muscle, inhibiting gluconeogenesis, and regulating lipid and protein metabolism. Measuring insulin in blood provides a direct window into pancreatic beta cell function and peripheral insulin sensitivity. The

1. Overview: What this test reveals and why it is important Zinc is an essential trace element required for the function of over 300 enzymes and the structural integrity of thousands of proteins. It plays indispensable roles in: · Immune function: T‑cell development, B‑cell antibody production, natural killer cell activity. · Wound healing: Collagen synthesis, cell proliferation, protein synthesis. · Growth and development: Cell division, DNA synthesis, childhood growth. · Sk

1. Overview: What this test reveals and why it is important The complement system is a cascade of more than 30 proteins that form a cornerstone of innate immunity. These proteins work in a carefully orchestrated sequence to: · Opsonise pathogens for phagocytosis. · Recruit and activate inflammatory cells via chemotaxis. · Form the membrane attack complex (MAC) to lyse bacteria and infected cells. · Clear immune complexes and apoptotic debris – a critical housekeeping function

1. Overview: What this test reveals and why it is important C-peptide (connecting peptide) is a short polypeptide chain that is cleaved from proinsulin during the enzymatic conversion to insulin within the pancreatic beta cells. Insulin and C-peptide are secreted into the portal circulation in equimolar concentrations. However, their fates diverge: insulin undergoes extensive first‑pass hepatic extraction (60–80%) and has a short half‑life (4–6 minutes), while C‑peptide exper

1. Overview: What this test reveals and why it is important Anti-Smith (Anti-Sm) antibodies are autoantibodies directed against protein components of the spliceosome complex – specifically the Sm core proteins (B/B', D1, D2, D3, E, F, G) bound to small nuclear ribonucleoproteins (snRNPs). These antibodies are named after the patient, Stephanie Smith, in whom they were first identified in 1966. Anti-Sm is the most specific serological marker for systemic lupus erythematosus (S

1. Overview: What this test reveals and why it is important Anti‑double‑stranded DNA (anti‑dsDNA) antibodies are autoantibodies directed against the helical structure of native, double‑stranded DNA. They are the most specific serological marker for systemic lupus erythematosus (SLE) , with a specificity exceeding 95% in the appropriate clinical context. Unlike many other autoantibodies, anti‑dsDNA is not merely a diagnostic marker – it is directly pathogenic. These antibodies

1. Overview: What this test reveals and why it is important Anti‑SSB/La antibodies are autoantibodies directed against the La protein, a 48‑kDa phosphoprotein involved in RNA processing and termination of RNA polymerase III transcription. The La protein is primarily nuclear but shuttles between nucleus and cytoplasm. These antibodies are almost always found together with Anti‑Ro/SSA antibodies, and their presence defines a specific serological profile in autoimmune rheumatic

1. Overview: What this test reveals and why it is important Anti-SSA/Ro antibodies are autoantibodies directed against intracellular ribonucleoprotein complexes. They are classified into two subtypes: Anti-Ro52 and Anti-Ro60, named for their molecular weight targets. These antibodies are directed against proteins bound to small cytoplasmic RNA molecules (hYRNA). The "SSA" stands for Sjögren's syndrome-related antigen A, and "Ro" is derived from the surname of the first patien

1. Overview: What this test reveals and why it is important Thyroglobulin (Tg) is a large glycoprotein produced exclusively by thyroid follicular cells. It serves as the scaffold for thyroid hormone synthesis and is stored within the follicular lumen. Anti‑thyroglobulin antibodies (Anti‑Tg, TgAb) are autoantibodies directed against this protein, primarily of the IgG class. The presence of Anti‑Tg antibodies has two distinct clinical contexts: 1. Autoimmune thyroid disease (AI

1. Overview: What this test reveals and why it is important Thyroid peroxidase (TPO) is a critical enzyme located in the thyroid follicular cells. It catalyses the iodination of tyrosine residues on thyroglobulin and the coupling of iodotyrosines to form the thyroid hormones T3 and T4. Anti‑TPO antibodies (TPOAb) are autoantibodies directed against this enzyme, primarily of the IgG class. The presence of TPOAb indicates autoimmune thyroid disease (AITD) , the most common orga