New turbidimetric Retinol-Binding Protein (RBP) immunoassay

12. Oct 2023 | 8 min read

New turbidimetric Retinol-Binding Protein (RBP) immunoassay

Quantitative determination of Retinol-Binding Protein levels in plasma and serum

Retinol-Binding Protein (RBP or RBP4) is a transport protein for retinol (vitamin A) in blood, synthesised in the liver and almost completely reabsorbed in the kidney.[1, 2] The concentration of RBP in blood remains mostly constant in healthy individuals, though the levels can be altered in many conditions and disorders such as vitamin A deficiency, undernutrition, diabetes and renal dysfunction. The RBP levels are elevated in patients with diabetes and renal dysfunction and reduced in conditions such as vitamin A deficiency and undernutrition.1,2


Diagnostic value 

The diagnostic value lies in altered levels of circulating RBP in many conditions, including:

Vitamin A deficiency2-5

Increasing prevalence of vitamin deficiency due to smoking, sedentary lifestyle, consumption of unhealthy food and alcohol


Growing geriatric population contributes to number of patients with undernutrition


With aging populations, a global increase in the incidence of chronic diseases such as diabetes is observed 

Renal dysfunction14-17

Rising prevalence of hypertension, type 2 diabetes, rising prevalence of kidney disease, and fast-growing geriatric population.


Potential target patient groups:

Vitamin A deficiency

  • Symptoms of vitamin A deficiency
  • Developing countries (replacing HPLC)
  • Undernourished patients


  • Suspected of developing diabetes
  • Obesity
  • Screening of pregnancy-related diabetes


  • Geriatric population
  • Disorders or on treatment affecting nutritional absorbance
  • Pediatric cancer
  • General health profile screening
  • Eating disorders or alcoholism

Renal dysfunction

  • Kidney failure
  • Individuals at risk of developing kidney failure
  • ICU for screening purposes


RBP - Retinol-Binding Protein


Advantages: the Gentian Retinol-Binding Immunoassay

Gentian Retinol-Binding Protein Immunoassay is a turbidimetric assay that is rapidly performed in only 10 minutes. The assay is instrument independent and can be applied on a wide range of automated clinical chemistry analysers.

  • Turbidimetric assay for serum and plasma
  • Instrument-independent
  • High-throughput analysis with standard core lab workflow
  • Ready-to-use Reagent Kit, Calibrator Kit and Controls
  • CE-marked and UKCA-marked
  • FDA 510 (k) exempt
  • Manufactured according to ISO 13485:2016


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Contact us for further information

Explore RBP in your laboratory - fill out the form below or send an email to for more information about the product and prices.




  1. Steinhoff JS et al. Retinoid Homeostasis and Beyond: How Retinol Binding Protein 4 Contributes to Health and Disease. Nutrients, 2022
  2. Tanumihardjo SA et al. Biomarkers of Nutrition for Development (BOND)-Vitamin A Review. J Nutr, 2016
  3. Gamble MV et al. Retinol binding protein as a surrogate measure for serum retinol: studies in vitamin A-deficient children from the Republic of the Marshall Islands. Am J Clin Nutr, 2001
  4. de Pee S et al. Biochemical indicators of vitamin A deficiency: serum retinol and serum retinol binding protein. J Nutr, 2002
  5. Talsma EF et al. Proxy markers of serum retinol concentration, used alone and in combination, to assess population vitamin A status in Kenyan children: a cross-sectional study. BMC Med, 2015
  6. Smith FR et al. Plasma vitamin A, retinol-binding protein and prealbumin concentrations in protein-calorie malnutrition. III. Response to varying dietary treatments. Am J Clin Nutr, 1975
  7. Sergi G et al. Role of visceral proteins in detecting malnutrition in the elderly. Eur J Clin Nutr, 2006
  8. Pisprasert V et al. Moderately high-protein enteral formula improved retinol-binding protein in tube-fed patients: A multicentre open study. Nutr Health, 2017
  9. Olsen T et al. Retinol, Retinoic Acid, and Retinol-Binding Protein 4 are Differentially Associated with Cardiovascular Disease, Type 2 Diabetes, and Obesity: An Overview of Human Studies. Adv Nutr, 2020
  10. Nono Nankam PA et al. Retinol-binding protein 4 in obesity and metabolic dysfunctions. Mol Cell Endocrinol, 2021
  11. Steinhoff JS et al. Biological Functions of RBP4 and Its Relevance for Human Diseases. Front Physiol, 2021
  12. Flores-Cortez YA et al. Interplay of retinol binding protein 4 with obesity and associated chronic alterations (Review). Mol Med Rep, 2022
  13. Mousavi SN et al. Association of Leptin and Retinol Binding Protein 4 with the Risk of Gestational Diabetes: A Systematic Review and Meta-Analysis of Observational Studies. Indian J Endocrinol Metab, 2023
  14. Zhang L et al. The Role of Circulating RBP4 in the Type 2 Diabetes Patients with Kidney Diseases: A Systematic Review and Meta-Analysis. Dis Markers, 2020
  15. Zhang WX et al. Decreased retinol-binding protein 4 in the sera of patients with end-stage renal disease after kidney transplantation. Genet Mol Res, 2014
  16. Xun C et al. Circulating RBP4 Increase and Its Diagnosis of Chronic Kidney Disease. Ann Clin Lab Sci, 2018
  17. Ye Z et al. Correlation and Diagnostic Value of Serum Cys-C, RBP4, and NGAL with the Condition of Patients with Traumatic Acute Kidney Injury. Evid Based Complement Alternat Med, 2021


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