## 1 Introduction  
Gluten is described as a \"protein component from wheat, rye, barley, oats or their crossbred varieties and derivatives thereof, to which some individuals are intolerant and that is insoluble in water and 0.5 mol/L NaCl\" by the Codex Alimentarius [1]. These are some of the most consumed cereals in the world and are frequently utilized in food processing; thus, patients suffering from gluten disorders require particularly careful treatment. Gluten-related disorders, such as celiac disease (CD), are among the most common food hypersensitivities worldwide, with a prevalence of around 1% in countries including Turkviye with a population of predominantly European origin [2, 3]. Other gluten-related disorders include dermatitis herpetiformis, gluten ataxia, non-celiac gluten sensitivity, and wheat allergy. Together, these conditions affect 1-6% of the global population [4]. Currently, the only recognized treatment strategy for these disorders is a gluten-free diet for life [5]. For a healthy lifestyle, people with gluten disorders must eliminate gluten from their diet and eat gluten-free foods on a regular basis. Currently, gluten-free foods are being consumed not only by those with gluten intolerance, but also by people who are interested in consuming them for health and wellness or weight control [6]. Following a gluten-free diet can be challenging due to the contamination of \"gluten free\" products, inaccurate labeling, societal pressures, and the widespread presence of gluten in food and medication. As a result, accidental ingestion of gluten is common. While most people with celiac disease can tolerate small amounts of gluten, such as 10 mg per day, there is a wide range of tolerance among individuals, and some may experience adverse effects from even small amounts of gluten exposure, such as inflammation in the small intestine, resulting in damage to the intestinal mucosa and eventually leading to problems with nutrient absorption [7; 8; 9; 10]. By combining toxicity data with observed food intakes, it has been determined that it is safe to consume gluten-free products (GFPs) that have a gluten contamination level of less than 20 mg/kg. This threshold of 20 ppm for gluten-free foods has been endorsed by official organizations such as the Codex Alimentarius [1; 11]. Products that do not contain gluten can be divided into two categories: those that are naturally gluten-free and those that have been processed to remove gluten. However, it can be challenging to completely avoid gluten in one's diet because gluten is a commonly used ingredient that can easily spread to products that are typically gluten-free during various stages of the production process, including growing, milling, storing, manufacturing, restaurants, and households [12; 13; 14]. Additionally, wheat flour or purified gluten is often added to various food products to improve their technological structure. In recent years, due to an increasing interest in healthy eating and the rise in gluten-related disorders, there has been a growing demand for gluten-free products. In response to this demand, the food industry has increased its supply of gluten-free products. However, with an increasing variety and number of products, there are concerns that contamination-related issues may become a major problem. The lack of data on contamination is a cause for concern. Immunological techniques such as ELISA are typically utilized in protein-based methods. The use of immunological approaches for gluten detection is prevalent. Each technique used to determine the amount of gluten present has unique characteristics, such as the format, the type of buffer used to extract the samples, the time and temperature required for extraction, the characteristics of the antibodies, the recognition epitope, and the reference material used for calibration. The distinct characteristics of each gluten quantification method and the lack of an authorized reference material may result in consistent variations in the obtained outcomes.