Physical Function ICU Test (PFIT)

Fysiobasen
Sep 17
3 min read

The Physical Function ICU Test (PFIT) is a clinical assessment tool developed to evaluate physical function in critically ill patients in the intensive care unit (ICU). Its primary goal is to measure strength, endurance, and mobility, providing guidance for rehabilitation and predicting functional outcomes after an ICU stay¹.

Target Group

PFIT is intended for:

Critically ill patients in the ICU
Patients undergoing mechanical ventilation
Individuals with severe weakness or deconditioning following prolonged immobility

It is particularly useful for monitoring progress during early mobilization programs and for identifying patients at high risk of long-term disability².

Målgruppe

PFIT er spesielt utviklet for kritisk syke pasienter på intensivavdelingen, særlig de som har utviklet ICU-erhvervet svakhet (ICUAW) eller hatt langvarig ICU-opphold. Testen er egnet for pasienter med tilstrekkelig bevissthet og fysisk kapasitet til å utføre enkle funksjonelle bevegelser⁴.

Method

The PFIT is performed at the bedside and requires minimal equipment. It consists of four core components:

Sit-to-stand assistance – ability to rise from a chair (graded according to level of assistance needed).
Marching in place – number of steps a patient can take while standing (up to 10).
Shoulder strength – isometric shoulder flexion graded against resistance.
Knee strength – isometric knee extension graded against resistance.

Each component is scored on a scale, and the combined total represents the patient’s functional capacity.

Scoring

Each item is scored 0–3 or 0–4 depending on the domain, with higher scores reflecting better performance.
Total scores can range from 0 (severely impaired) to 12 (normal physical capacity).
Scores can be converted into the PFIT-s (short version), which has been validated for reliability and responsiveness³.

Administration

The test takes 5–10 minutes to administer.
Requires a chair, stop-watch, and resistance applied manually by the assessor.
Must be performed by trained physiotherapists or ICU clinicians familiar with mobilization protocols.

Reliability and Validity

Reliability: PFIT and PFIT-s demonstrate strong inter-rater reliability and internal consistency (ICC > 0.95).
Validity: Correlates strongly with other functional outcome measures such as the 6-Minute Walk Test (6MWT), handgrip strength, and Barthel Index⁴.
Responsiveness: Sensitive to changes during ICU stay and rehabilitation, making it a suitable outcome measure in both clinical and research settings³.

Clinical Relevance

PFIT provides clinicians with:

A structured framework to guide early mobilization in ICU patients.
Objective data to track patient progress.
Prognostic insight into post-ICU physical recovery.

Patients with higher PFIT scores at ICU discharge have been shown to achieve faster recovery and greater independence in daily life activities⁵.

Limitations

May not be feasible in patients with extreme instability or contraindications to mobilization.
Requires skilled staff to ensure safety during sit-to-stand and marching tasks.
Some patients may not tolerate testing due to fatigue or medical equipment constraints.

Conclusion

The Physical Function ICU Test is a validated, reliable, and practical assessment tool for evaluating physical function in critically ill patients. It plays a crucial role in guiding rehabilitation strategies, predicting recovery outcomes, and supporting early mobilization efforts in the ICU.