An enzyme immunoassay for determining albumin in human urine samples using an ultra-microanalytical system

ABSTRACT

Microalbuminuria is a term to describe a moderate increase in the level of albumin in urine. It is an important prognostic marker for kidney damage in diseases such as diabetes mellitus and hypertension. A simple sandwich-type ultramicroELISA assay (UMELISA) has been developed for the measurement of albumin in human urine samples. Strips coated with a high affinity monoclonal antibody directed against albumin are used as solid phase, to ensure the specificity of the assay. The albumin assay was completed in 1 hr and 30 min, with a measuring range of 1.44–200 ng/mL. The intra- and inter-assay coefficients of variation were 3.98–4.35% and 7.59–8.92%, respectively, depending on the albumin concentrations evaluated. Percentage recovery ranged from 94.26 to 98.50%. Regression analysis showed a good correlation with the commercial quantitative turbidimetric test Microalbumin-turbilatex (n = 240, r = 0.994, p < .01). The analytical performance characteristics of our UMELISA MICROALBUMINA endorse its use for the quantification of albumin in human urine samples. This test will make a cost-effective diagnostic kit accessible to low-income countries such as Latin American countries and is now available in the Cuban Public Health System.

KEYWORDS:

• Microalbuminuria
• early diagnosis kidney damage
• ultramicroELISA
• diabetes mellitus
• hypertension

Highlights

- Microalbuminuria is an important prognostic marker for kidney damage.

- UMELISA MICROALBUMINA is an assay for albumin measurement in human urine samples.

- This is a cost-effective diagnostic kit used in the Cuban Public Health System.

Author agreement

Title of the manuscript: An enzyme immunoassay for determining albumin in human urine samples using an ultra-microanalytical system.

“All the authors have made a significant contribution to this manuscript, have seen and approved the final manuscript, and have agreed to its submission to the “Journal of Immunoassay & Immunochemistry “.

Compliance with ethical standards

Highlights

- Microalbuminuria is an important prognostic marker for kidney damage.

- UMELISA MICROALBUMINA is an assay for albumin measurement in human urine samples.

- This is a cost-effective diagnostic kit used in the Cuban Public Health System.

CRediT author statement

-Ruben del Valle García: Literature search, standardization of the assay, figures, study design, data collection, data analysis, data interpretation, investigation, writing, supervised the project.

-Juliette M. Cazanave Mora: Data analysis, data interpretation, plates coating, supervised the project.

-Nancy L. Carrazana San Martín: Data analysis, data collection, plates coating, investigation, supervised the project.

-Liliana Hernández Pérez: Literature search, purification of albumin, obtaining the conjugated antibody, data analysis, data collection.

-Martha E. Legrá Torres: Data collection, Investigation.

-Raquel López Cisneros: Obtaining the conjugated antibody, purification of albumin, data collection.

-Rainald P. Ordaz Ramos: Data collection, Investigation.

-Antonio Melchor Rodríguez: Data interpretation, supervised the project.

-Irinia Valdivia Álvarez: Data interpretation, supervised the project.

Disclosure statement

The authors declare that they have no conflict of interest

Ethics

This work complies with the principles laid down in the Declaration of Helsinki “Recommendations guiding physicians in biomedical research involving human subjects”, adopted by the 18th World Medical Assembly, Helsinki, Finland, June 1964 (and its successive amendments). This work has been approved by the appropriate ethical committees related to the institution(s) in which it was performed. Studies involving experiments with animals following the Guide for the Care and Use of Laboratory Animals and their care was in accordance with institution guidelines.

List of abbreviations

CV: Coefficient of variation

ELISA: Enzyme-linked immunosorbent assay

FU: Fluorescence units

IU: International units

LOB: Limit of blank

LOD: Limit of detection

LOQ: Limit of quantitation

MA: Microalbuminuria

PBS: Phosphate-buffered saline solution

SD: Standard deviation

SUMA: Ultra Micro Analytic System

UMELISA: Ultramicro enzyme-linked immunosorbent assay

Additional information

Funding

None