Introduction
- Vitamin D is a steroid hormone involved in the active intestinal absorption of calcium and in the regulation of its homeostasis.
- Vitamin D has 2 forms:
- Vitamin D2 (Ergocalciferol) &
- Vitamin D3 (Cholecalciferol)
Source of Vitamin D
Vitamin D often referred to as the “sunshine vitamin”. It can be obtained through sunlight, fatty fish, fortified foods, egg yolks, liver, mushrooms, and supplements. It’s essential to maintain a balanced diet and get regular exposure to sunlight to ensure adequate levels of vitamin D in the body.
Why Vitamin D is important?
Vitamin D is a fat-soluble nutrient essential for various physiological functions within the human body due to its role in maintaining overall health and well-being.
- Bone health– Vitamin D plays a crucial role in calcium absorption in the intestines. It promotes formation and mineralization of bones and teeth.
- Immune system support– Vitamin D is involved in the modulation of the immune system.
- Muscle function– Vitamin D is essential for muscle function and strength. It plays a role in the development and maintenance of muscle tissue.
- Cell growth and differentiation– Vitamin D is involved in the regulation of cell growth, proliferation, and differentiation. It has implications in various cellular processes and may play a role in preventing the development of certain cancers.
- Cardiovascular health– There is evidence suggesting that vitamin D may have a role in cardiovascular health. Adequate levels of vitamin D are associated with a lower risk of cardiovascular diseases, including hypertension and heart attacks.
- Mood and mental health– Vitamin D receptors are present in the brain, and emerging research suggests a potential link between vitamin D levels and mood disorders.
- Regulation of Insulin levels– Vitamin D may play a role in insulin sensitivity and the regulation of blood sugar levels. Adequate vitamin D levels are associated with a lower risk of developing type 2 diabetes.
- Anti -inflammatory effects– Vitamin D has anti-inflammatory properties and may help modulate the inflammatory response in the body. Chronic inflammation is linked to various chronic diseases, and vitamin D may contribute to overall inflammation regulation.
Factors and clinical conditions affecting Vitamin D level in the body
- Sunlight exposure– Factors such as geographical location, season, air pollution, and sunscreen use can influence the amount of ultraviolet B (UVB) radiation reaching the skin, thereby affecting vitamin D synthesis.
- Skin pigmentation– Individuals with darker skin require more extended sun exposure to produce the same amount of vitamin D as those with lighter skin due to high level of skin pigment Melanin responsible for skin color.
- Dietary intake– Dietary choices and restrictions, such as veganism or lactose intolerance, can affect vitamin D intake.
- Obesity– Obesity is associated with lower circulating levels of vitamin D due to the storage of Vitamin D in adipose (fat) tissues reducing its availability in bloodstream.
- Malabsorption disorder– Conditions such as celiac diseases, Crohn’s disease and other gastrointestinal disorders can impair the absorption of dietary vitamin D, leading to deficiency.
- Liver & Kidney disease– Liver diseases such as cirrhosis and hepatitis and chronic kidney diseases can impair the conversion of vitamin D to its active form (Calcitriol) in liver and kidneys resulting into deficiency of vitamin D levels.
- Hyperparathyroidism– Overactivity of the parathyroid glands, leads to increased secretion of parathyroid hormone, can affect calcium and phosphorus metabolism and impact vitamin D levels
- Hypercalcemia– Elevated levels of calcium in the blood can occur in conditions such as hyperparathyroidism, certain cancers, or granulomatous diseases, impacting vitamin D metabolism.
- Genetic factors– Individual’s with genetic variations are more susceptible to vitamin D deficiency or sufficiency.
Symptoms of Vitamin D deficiency
- Weakened bones, contributing to conditions like rickets in children and osteomalacia in adults.
- Susceptibility to infections and autoimmune diseases.
- Muscle weakness and an increased risk of falls, especially in older adults.
- Bone deformities in childrens
- Depression and seasonal affective disorder (SAD)
- Increased risk of chronic diseases
- Delayed wound healing
Reference range of Vitamin D
- Deficiency- <20ng/mL
- Insufficiency- 21 – 29ng/mL
- Sufficiency- >30ng/mL
Source: Vitamin D deficiency in India; Journal of Family Medicine and Primary Care7(2):324-330, Mar-Apr 2018.
Methods for determination of Vitamin D
There are many methods available for the determination of Vitamin D in the body. These methods vary in terms of specificity, sensitivity, and complexity. The choice of the methods depends on factors such as laboratory’s capabilities, the required sensitivity and specificity, sample volume and intended use (clinical diagnosis or research purpose).
- Immuno-Turbidimetry
- RadioImmunoassay (RIA)
- Enzyme Linked Immunosorbant Assay (ELISA)
- Chemiluminescence Assay (CLIA)
- Point-of-Care Testing (POCT)
- Liquid Chromatography Tandem Mass Spectrometry (LCTMS)
Direct particle-enhanced Immuno-Turbidimetry
AGD Vitamin D TurbiPak is intended for use in clinical laboratories for the quantitative determination of 25-OH vitamin D in human serum and plasma using automated chemistry analyzers. AGD TurbiPak based on Direct particle-enhanced immuno-turbidimetry assay consists of two reagents that are designed to dissociate Vitamin D from vitamin D binding proteins, found in serum or plasma specimens, while particle coated with anti-vitamin D antibodies bind to the dissociated vitamin, thereby causing agglutination. The agglutination is detected as an absorbance change with the magnitude of the change being proportional to the quantity of total vitamin D in the sample.
Benefits of AGD Vitamin D TurbiPak
- No sample pre-treatment or pre-dilutions required
- It can be programmed on different automatic analyzers
- Result in 8 minutes
- Wide assay range- 7.6 – 147.8 ng/mL
- Available in various pack sizes depending on customer workload and choices
- 5 calibrators of known concentration included in each kit
- Pack size- 1 x 10mL | 1 x 20mL
