IDDSI Level 2: Mildly Thick

IDDSI Level 2 — Mildly Thick is a liquid consistency that flows noticeably slower than water and Level 1 but still pours from a cup. Under the older National Dysphagia Diet (NDD) system it was called “nectar-thick”, a term still heard in Hong Kong clinical settings today, though IDDSI has moved away from food metaphors to reduce international ambiguity.

At Level 2, the liquid should feel slightly coat-forming in the mouth — not syrup-thick, but noticeably more resistant than thin juice. This extra viscosity buys the pharyngeal swallowing reflex a crucial fraction of a second, reducing aspiration risk in patients with mild-to-moderate pharyngeal dysphagia.

IDDSI Syringe Flow Test — Level 2 Criteria

The standard IDDSI 10 ml syringe test distinguishes Level 2 from adjacent levels:

Test procedure:

1. Draw 10 ml of the prepared liquid into a standard 10 ml Luer slip syringe (no needle).
2. Hold vertically, tip pointing down; occlude the tip with one finger.
3. Start a timer and simultaneously release your finger.
4. At exactly 10 seconds, re-occlude the tip.
5. Read the residual volume against the barrel markings.

A result of 4–8 ml remaining confirms Level 2. If residual is below 4 ml, the liquid is too thin (add more thickener); above 8 ml means you have overshot to Level 3.

Why 10 ml and 10 seconds? The IDDSI Research Committee validated these parameters across multiple lab and clinical sites internationally. Using a different syringe size or timing window invalidates the result.

Who Is Level 2 Prescribed For?

Level 2 is commonly recommended for patients where thin liquids pose aspiration risk but who can tolerate faster-flowing thickened drinks without fatigue. Clinical profiles include:

• Subacute stroke with mild pharyngeal delay — thin liquids aspirate; Level 2 provides adequate transit time without the weight of Level 3
• Parkinson’s disease (early-to-mid stage) — slowedlaryngeal elevation and cricopharyngeal stiffness benefit from mild thickening; full Level 3 may impair quality of life
• Dementia with mild swallowing impairment — mild thickening is often better tolerated than moderate, maintaining fluid intake compliance
• Geriatric frailty — generalised pharyngeal weakness with intact cough reflex; Level 2 reduces silentaspiration events during night drinks
• Head and neck cancer (post-treatment) — oedema and reduced pharyngeal clearance in the weeks after radiotherapy

A speech-language pathologist (言語治療師, SLT) must prescribe the appropriate level following a formal swallowing assessment such as the GUSS, MBSS, or FEES.

Nectar Consistency vs IDDSI Level 2

Many Hong Kong facilities and families still refer to “nectar-thick” from the earlier NDD classification. The two systems are broadly equivalent but not identical:

IDDSI Level 2 is the current international standard. The Hospital Authority (HA) and the Hong Kong Institute of Occupational Therapists and Speech Therapists have moved toward IDDSI terminology. Facilities still using “nectar” should consider updating their diet cards and staff training to IDDSI language.

Thickener Preparation for Level 2 in Hong Kong

Starch-Based Thickeners

Starch thickeners (modified corn starch, tapioca starch) are widely available and used in many Hong Kong RCHEs due to cost. Key points for Level 2:

• Starch thickeners continue to thicken as liquid cools or sits. A drink prepared at Level 2 when warm may test at Level 3 thirty minutes later.
• Re-test at serving temperature, not preparation temperature.
• Stirring time matters: allow 30–60 seconds of vigorous stirring before testing.
• Typical starting quantity: 1.5–2 scoops per 200 ml (vary by brand; always verify with flow test).

Xanthan Gum-Based Thickeners

Xanthan gum thickeners (e.g. Resource ThickenUp Clear, Nutilis Clear) are thermostable — consistency is maintained whether hot, cold, or room temperature. This makes them preferable for:

• Residents who sip drinks slowly over 30+ minutes
• Iced drinks or cold herbal tea served in summer
• Any situation where preparation-to-serving time is unpredictable

Typical starting quantity for Level 2: 1–1.5 g per 200 ml (brand-specific; verify with flow test).

Practical Preparation Card (for care home kitchens)

IDDSI Level 2 — Mildly Thick
Drink: ____________  Volume: 200 ml
Thickener brand: ____________
Quantity: ______ g / scoops
Stirring: 30 sec vigorous
Standing time: _____ min
Flow test result: _____ ml remaining  ✓ Pass / ✗ Fail
Prepared by: _________  Time: _______

A laminated preparation card at each care station reduces inter-shift variability.

Common Hong Kong Drinks and Level 2 Considerations

Patient and Caregiver Experience

Level 2 liquids are noticeably different from water but most patients adapt within a few days. Common concerns:

“I don’t feel thirsty when the drink is thick.” Thickened liquids can reduce subjective thirst perception. Schedule regular drink times (every 1–2 hours) rather than relying on thirst cues. Hydration monitoring is essential — document fluid intake volume daily.

“The texture changes between morning and evening.” Starch thickeners drift with temperature and time. Switching to a xanthan gum product, or creating a written preparation standard for each shift, addresses this.

“My relative refuses to drink.” Flavour-neutral xanthan gum thickeners minimise taste change. Offering preferred drinks (e.g. a favourite herbal tea or warm soy milk) at Level 2 rather than plain water improves acceptance. Small, frequent sips at a comfortable pace are easier than large volumes.

Hong Kong Care Home (RCHE) Implementation

Under the Social Welfare Department (SWD) Code of Practice for Residential Care Homes for the Elderly, care homes are expected to follow dietary prescriptions from healthcare professionals. In practice, IDDSI implementation requires:

1. SLT diet card system — each resident’s current IDDSI liquid level recorded, updated after each reassessment
2. Kitchen staff training — annual or semi-annual hands-on thickener preparation training with flow test verification
3. Care staff training — all personal care staff understand which residents require thickened liquids and at what level
4. Visitor communication — families must be informed; a common error is well-meaning relatives bringing thin drinks (e.g. 維他奶, fruit juice) without realising thickening is required
5. Incident reporting — any choking, coughing during drinks, or suspected aspiration should be documented and trigger SLT review

Monitoring and Reassessment

Dysphagia is not static. Patients may improve (allowing step-down to Level 1 or 0) or deteriorate (requiring step-up to Level 3). Signs warranting SLT reassessment:

• Increased coughing or throat-clearing during or after drinks
• Wet or gurgling voice quality after drinking
• Unexplained recurrent chest infections
• Weight loss or dehydration
• Patient reports difficulty swallowing even thickened drinks
• Significant change in neurological or medical status

References

• IDDSI Committee. (2019). IDDSI Framework: Complete Definitions. iddsi.org.
• Cichero JAY, et al. (2017). Development of International Terminology and Definitions for Texture-Modified Foods and Thickened Fluids Used in Dysphagia Management. Dysphagia, 32(2), 293–314.
• Hospital Authority Hong Kong. (2021). IDDSI Implementation Guidance for HA Clinical Settings. Internal circular.
• National Dysphagia Diet Task Force. (2002). National Dysphagia Diet: Standardization for Optimal Care. American Dietetic Association.
• Steele CM, et al. (2015). The influence of food texture and liquid consistency modification on swallowing physiology and function. Dysphagia, 30(2), 119–128.

This page is for educational purposes only. IDDSI level prescriptions must be made by a qualified speech-language pathologist following individual clinical assessment.