Understanding the International Dysphagia Diet Standardisation Initiative (IDDSI)
The International Dysphagia Diet Standardisation Initiative, or IDDSI, was established to create a global framework for describing texture-modified foods and thickened liquids for people with dysphagia. Before IDDSI, there was no consistent standard, leading to confusion and potential safety risks for individuals requiring modified diets. The framework uses numbers, text labels, and color codes to provide a universal language for healthcare professionals, caregivers, and patients. The full IDDSI framework includes a continuum of 8 levels (0-7), with drinks categorized from Levels 0–4 and foods from Levels 3–7.
The implementation of this standardized system has drastically improved patient safety by reducing the guesswork associated with preparing thickened liquids. It also facilitates smoother transitions for patients moving between different care settings, as the diet recommendations no longer require complex translation. Adherence to IDDSI guidelines ensures consistency and accuracy in meal preparation, which is vital for preventing aspiration pneumonia and other complications associated with dysphagia.
What is the IDDSI drink scale?
The IDDSI drink scale specifically addresses liquids, classifying them into five distinct levels based on their viscosity or thickness. The higher the level, the thicker the liquid. This helps match the liquid's flow rate to an individual's swallowing ability, as determined by a clinical assessment.
IDDSI Drink Scale Levels
- Level 0 - Thin (Color: Green): This level includes all regular, un-thickened liquids such as water, milk, coffee, and juice. They flow quickly and freely, similar to water, and are only safe for individuals with no swallowing difficulties with liquids. They can be consumed via a cup or straw.
- Level 1 - Slightly Thick (Color: Grey): Slightly thicker than water, these liquids flow through a straw but more slowly than Level 0. Some fruit nectars may naturally fall into this category. They offer a bit more control during swallowing, which may benefit individuals with mild dysphagia.
- Level 2 - Mildly Thick (Color: Pink): These liquids are thicker than Slightly Thick liquids and require more effort to drink through a straw. They pour slowly from a spoon and are described as 'sippable.' If testing, 4-8mL of liquid should remain in a 10mL syringe after 10 seconds.
- Level 3 - Moderately Thick (Color: Blue): Liquids at this level can be drunk from a cup or spoon but require significant effort to pass through a wide straw. They are smooth with no lumps and have a much slower flow rate. When tested with a 10mL syringe, 8-10mL of liquid will remain after 10 seconds. This level also overlaps with food textures known as Liquidised.
- Level 4 - Extremely Thick (Color: Yellow): This is the thickest drink level, with a consistency similar to pudding. These liquids do not flow through the prongs of a fork and must be eaten with a spoon. They hold their shape and are suitable for individuals with significant swallowing limitations who cannot manage thinner liquids. This level is also used for pureed foods.
How to Test Drink Thickness with the IDDSI Flow Test
The IDDSI Flow Test is a simple, objective way to check the thickness of liquids and liquidized foods from Levels 0-3 using a 10mL syringe. Level 4, which is non-flowing, is tested differently using fork and spoon methods.
Steps for the IDDSI Flow Test
- Gather Supplies: You will need a standard 10mL syringe and a timer. Syringes with a specific IDDSI marking may be available, but any standard syringe will work.
- Prepare the Liquid: Ensure the drink is at the temperature it will be served, as temperature can affect viscosity. Stir the liquid thoroughly to ensure a uniform consistency.
- Perform the Test:
- Place a finger over the nozzle of the syringe and pour the liquid up to the 10mL mark.
- Remove your finger and, simultaneously, start the timer.
- Wait exactly 10 seconds.
- Read the Result: After 10 seconds, place your finger back over the nozzle and read the volume of liquid remaining in the syringe. Use the following guide to determine the IDDSI level:
- Level 0 (Thin): <1 mL remaining.
- Level 1 (Slightly Thick): 1–4 mL remaining.
- Level 2 (Mildly Thick): 4–8 mL remaining.
- Level 3 (Moderately Thick): >8 mL remaining.
IDDSI Comparison Table
| IDDSI Level | Name | Syringe Test (mL remaining at 10s) | Consistency Characteristics | Example Drinks (Pre-modified) |
|---|---|---|---|---|
| 0 | Thin | < 1mL | Flows like water; fast flow | Water, Milk, Tea, Juice |
| 1 | Slightly Thick | 1–4 mL | Thicker than water; flows through straw | Some fruit nectars |
| 2 | Mildly Thick | 4–8 mL | Flows slower than Thin; sippable, some effort with straw | Yogurt drink |
| 3 | Moderately Thick | > 8 mL | Can be spooned; requires significant effort for straws | Some smoothies |
| 4 | Extremely Thick | 10 mL | Holds its shape; does not flow through fork | Pudding-like drinks |
Benefits and Practical Application for a Nutritious Diet
Proper use of the IDDSI drink scale is crucial for ensuring individuals with dysphagia receive adequate nutrition and hydration safely. Dehydration is a significant risk for those with swallowing difficulties, as they may reduce their fluid intake due to discomfort or fear of choking. By providing liquids at the correct thickness, IDDSI encourages better fluid intake while minimizing aspiration risk.
Beyond safety, the IDDSI framework also supports nutritional intake. Thickened drinks and liquidised foods can be fortified with nutritional supplements to provide essential energy and protein, which is especially important for underweight or frail individuals. For caregivers, IDDSI provides a clear, reliable system that removes much of the subjectivity and anxiety from preparing meals and drinks for their loved ones. Training for both caregivers and healthcare staff is essential for successful implementation and consistent application of the standards.
For more detailed information and resources, including printable guides and videos on testing methods, visit the official International Dysphagia Diet Standardisation Initiative website.
Conclusion
The IDDSI drink scale is a vital component of the broader International Dysphagia Diet Standardisation Initiative, offering a standardized, globally recognized system for classifying liquid thickness. This framework has transformed the management of dysphagia by improving safety, promoting consistent care, and ensuring adequate nutrition and hydration. For patients, caregivers, and healthcare professionals alike, understanding and correctly applying the IDDSI drink scale is a critical step towards better health outcomes and a higher quality of life. The use of simple testing methods, like the 10mL syringe flow test, empowers individuals to confirm the consistency of liquids with confidence, minimizing the risks associated with swallowing disorders.
