Retinol Binding Protein 4 (RBP4) ELISA Kit


Human RBP4 ELISA kit is designed for measuring in vitro quantitative levels of retinol binding protein 4 (RBP-4, RBP4) in human serum, plasma, many biological fluids and tissues homogenates. This assay has a minimum detection limit of 0.938 ng/ml.


Retinol binding protein 4 (RBP4, RBP-4) is a member of the lipocalin family and is a 21kDa secreted protein which has important roles in transporting retinol (vitamin A) to tissues. It has the ability to deliver retinol from the liver stores to the peripheral tissues and in plasma, the RBP-retinol complex can interact with transthyretin resulting in preventing its loss via kidney glomeruli. Any deficiency of vitamin A can lead to blocking the secretion of the binding protein post-translationally and this can cause a defective delivery and supply to the epidermal cells.

Elevated levels of serum retinol binding protein 4 have been correlated with type 2 diabetes and insulin resistance in several clinical studies. It has also been recently been described as an adipokine that can contribute to insulin resistance in the AG4KO mouse model, it is secreted by adipocytes and has a vital role in providing a signal to other cells under conditions where there is reduced levels of plasma glucose.

Clinical studies have recently found a correlation between elevated serum RBP4 level and subclinical inflammation, whereas other studies have revealed that RBP4 has the ability to induce inflammation in macrophages.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • One 96-Well Plate: Pre-coated with anti RBP-4 antibody.
  • Standards: Concentrations 0, 1.56, 3.125, 6.25, 12.5, 25, 50, 100 ng/ml, made up from lyophilized recombinant human retinol binding protein 4.
  • Sample/Standard Dilution Buffer.
  • Biotinylated-labelled RBP-4 Antibody.
  • Antibody Dilution Buffer.
  • HRP-Streptavidin Conjugate (SABC).
  • SABC Dilution Buffer.
  • TMB Substrate.
  • Wash Buffer (25x).
  • Plate Sealer.
  • Product Instructions.


The minimum detection sensitivity level of retinol binding protein 4 (RBP-4, RBP4) using current human RBP4 ELISA kit was 0.938 ng/ml. The dynamic range for this assay is 1.563 – 100 ng/ml.


– Retinol Binding Protein 4 (RBP4): ELISA
– Specificity: Highly specific for RBP-4, no cross reactivity or interference between RBP-4 and analogues was detected.
– Recovery: Serum (95 – 101%), EDTA Plasma (92 – 105%), Heparin Plasma (97 – 102%).
– Linearity: Serum (88 – 101%), EDTA Plasma (86 – 100%), Heparin Plasma (85 – 98%).
– Precison Intra-Assay: CV < 8%.
– Precison Inter-Assay: CV < 10%.
– Stability: Less than 10%.


  1. Is retinol binding protein 4 a link between adiposity and cancer? Horm Mol Biol Clin Investig. (2015) 23 (2): 39-46. Review. Noy N., et al.
  2. Serum retinol-binding protein: a link between obesity, insulin resistance, and type 2 diabetes. Nutr Rev. (2007) 65 (5): 251-6. Review. Wolf G.
  3. Vitamin A and Diabesity: New Insight for Drug Discovery. Mini Rev Med Chem. (2016) 16 (9): 738-42. Review. Cione E., et al.
  4. RBP4: a controversial adipokine. Eur J Endocrinol. (2011) 165 (5): 703-11. Review. Kotnik P., et al.
  5. Retinol-binding protein-4 in experimental and clinical metabolic disease. Expert Rev Mol Diagn. (2008) 8 (3): 289-99. Review. von Eynatten M. and Humpert P.M.


  • Full Name: Retinol Binding Protein 4 (RBP4) ELISA Kit
  • Reactivity: Human
  • Sample Type: Tissue Homogenates, Plasma, Biological Fluids, Serum
  • Sensitivity: 0.938 ng/ml



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