Predicted Total Lung Capacity

\[\begin{aligned} TLC_{male} &= 0.089H-0.019A-7.33 \\ TLC_{female} &= 0.075H-0.018A-5.05 \end{aligned}\]

Variables

TLCmalepredicted total lung capacity for males (L)

TLCfemalepredicted total lung capacity for females (L)

Hheight (cm)

Aage (years)

Description

What is this formula?

Predicted Total Lung Capacity (TLC) estimates the total volume of air contained in the lungs after a maximal inspiration. It is one of the primary reference values used to assess restrictive lung disorders.

When to use it

Use this formula when evaluating lung volumes, diagnosing restrictive pulmonary disease, interpreting body plethysmography results, or comparing measured TLC with expected normal values.

Example

Data:

Male

Height = 175 cm

Age = 40 years

Formula:

TLCmale = 0.089H − 0.019A − 7.33

Substitution:

TLCmale = (0.089 × 175) − (0.019 × 40) − 7.33

TLCmale = 15.575 − 0.760 − 7.330

TLCmale = 7.49 L

Result:

Predicted TLC = 7.49 L

Applications

- Body plethysmography

- Pulmonary function laboratories

- Restrictive lung disease assessment

- Occupational medicine

- Respiratory physiology

Note

This equation is an empirical prediction model derived from specific population studies. Numerous alternative reference equations exist, and modern pulmonary laboratories may use GLI-based or region-specific reference standards. Results should be interpreted according to local clinical guidelines.