Home > Services > Therapies > Speech and language therapy > Food and Fluid Terminology (IDDSI) > IDDSI Fluid Levels & Information

On this page:

4 – Extremely Thick
3 – Moderately Thick
2 – Mildly Thick
1 – Slightly Thick
0 – Thin

 

Level 4 – Extremely Thick

What is an extremely thick fluid? It is a fluid which:

  • Cannot be drunk from a cup
  • Cannot be sucked through a straw
  • Shows some very slow movement under gravity but cannot be poured
  • Should not be firm and sticky

Testing Method:

If you are unsure whether your drink is adequately thick for an Extremely Thick consistency you can test it using the spoon tilt test.

Take a spoonful of fluid and tip it off of the spoon. The fluid should be:

  • A cohesive enough to hold its shape on the spoon
  • The full spoonful must plop off spoon if tilted/turned sideways (sliding off easily with very little left on the spoon)

Click here for a printable IDDSI leaflet on extremely thick fluids and thickening guidelines

Level 3 – Moderately Thick

What is a moderately thick fluid? It is a fluid which:

  • Can be drunk from a cup
  • Some effort required to suck through a standard bore or wide bore straw (6.9mm diameter)

Testing Method:

If you are unsure whether your drink is adequately thick for a Moderately Thick consistency you can test it using the flow-rate test.

  • Remove the plunger from a 10 mls slip tip syringe
  • Fill the 10ml slip tip syringe with 10mls of your fluid, covering the tip so that no fluid runs out
  • Start a timer for 10 seconds & simultaneously uncover the tip of the syringe to allow the fluid to flow through
  • Cover the tip of the syringe after 10 seconds
  • Check how many mls are left in the syringe at this point
  • A Moderately Thick fluid should have more than 8mls left in the syringe after the 10 seconds

Click here for a printable IDDSI leaflet on Moderately thick fluids and thickening guidelines

Click here for an IDDSI YouTube Video demonstrating how to complete the flow-rate test.

 

Level 2 – Mildly Thick

What is a mildly thick fluid? It is a fluid which:

  • Flows off a spoon
  • Sippable, pours quickly from a spoon, but slower than unthickened drinks
  • Effort is required to drink this thickness through a standard bore straw (5.3mm diameter)

Testing Method:

If you are unsure whether your drink is adequately thick for a Mildly Thick consistency you can test it using the flow-rate test.

  • Remove the plunger from a 10 mls slip tip syringe
  • Fill the 10ml slip tip syringe with 10mls of your fluid, covering the tip so that no fluid runs out
  • Start a timer for 10 seconds & simultaneously uncover the tip of the syringe to allow the fluid to flow through
  • Cover the tip of the syringe after 10 seconds
  • Check how many mls are left in the syringe at this point
  • A Mildly Thick fluid should have more than 4-8mls left in the syringe after the 10 seconds

Click here for a printable IDDSI leaflet on Mildly thick fluids and thickening guidelines

Click here for an IDDSI YouTube Video demonstrating how to complete the flow-rate test.

 

Level 1 – Slightly Thick

What is a Slightly Thick fluid? It is a fluid which:

  • Is thicker than water
  • Requires a little more effort to drink than thin liquids
  • Flows through a straw, syringe, teat/nipple
  • Is similar to thickness of commercially available ‘anti-regurgitation’ formula

Testing Method:

If you are unsure whether your drink is adequately thick for a Slightly Thick consistency you can test it using the flow-rate test.

  • Remove the plunger from a 10 mls slip tip syringe
  • Fill the 10ml slip tip syringe with 10mls of your fluid, covering the tip so that no fluid runs out
  • Start a timer for 10 seconds & simultaneously uncover the tip of the syringe to allow the fluid to flow through
  • Cover the tip of the syringe after 10 seconds
  • Check how many mls are left in the syringe at this point
  • A Slightly Thick fluid should have more than 1-4mls left in the syringe after the 10 seconds

Click here for a printable IDDSI leaflet on slightly thick fluids and thickening guidelines

Click here for an IDDSI YouTube Video demonstrating how to complete the flow-rate.

 

Level 0 – Thin

What is a thin fluid? It is a fluid which:

  • Flows like water
  • Is fast flow
  • Can be drunk through any type of cup or straw

Testing Method:

If you are unsure whether your drink is a Thin fluid consistency you can test it using the flow-rate test.

  • Remove the plunger from a 10 mls slip tip syringe
  • Fill the 10ml slip tip syringe with 10mls of your fluid, covering the tip so that no fluid runs out
  • Start a timer for 10 seconds & simultaneously uncover the tip of the syringe to allow the fluid to flow through
  • Cover the tip of the syringe after 10 seconds
  • Check how many mls are left in the syringe at this point
  • A Thin fluid should have completely emptied after the 10 seconds with no residue left in the syringe

Click here for a printable IDDSI leaflet on thin fluids

 

The International Dysphagia Diet Standardisation Initiative 2016 – http://iddsi.org/framework/.
Attribution is NOT PERMITTED for derivative works incorporating any alterations to the IDDSI Framework that extend beyond language translation. Supplementary Notice: Modification of the diagrams or descriptors within the IDDSI Framework is DISCOURAGED and NOT RECOMMENDED. Alterations to elements of the IDDSI framework may lead to confusion and errors in diet texture or drink selection for patients with dysphagia. Such errors have previously been associated with adverse events including choking and death.