Transfer Factor

Question 1

What does the transfer factor (TLCO) measure?

Answer 1

The rate of gas diffusion from alveoli into pulmonary capillary blood, assessed using carbon monoxide.

Question 2

What does the transfer coefficient (KCO) represent?

Answer 2

TLCO corrected for alveolar volume (i.e. diffusion efficiency per unit lung volume).

Question 3

Which obstructive lung disease causes a raised TLCO?

Answer 3

Asthma (due to increased pulmonary blood volume).

Question 4

Which bleeding-related conditions increase TLCO?

Answer 4

Pulmonary haemorrhage disorders such as GPA (Wegener’s) and Goodpasture’s.

Question 5

Which cardiovascular anomaly increases TLCO?

Answer 5

Left-to-right cardiac shunts.

Question 6

Which blood abnormality raises TLCO?

Answer 6

Polycythaemia.

Question 7

Which physiological states raise TLCO?

Answer 7

Male sex, exercise, hyperkinetic states.

Question 8

Which interstitial lung disease classically lowers TLCO?

Answer 8

Pulmonary fibrosis.

Question 9

Which acute lung infection reduces TLCO?

Answer 9

Pneumonia.

Question 10

Which vascular condition lowers TLCO?

Answer 10

Pulmonary embolism.

Question 11

Which cardiogenic condition reduces TLCO?

Answer 11

Pulmonary oedema.

Question 12

Which obstructive disease lowers TLCO due to alveolar destruction?

Answer 12

Emphysema.

Question 13

Which haematological condition lowers TLCO?

Answer 13

Anaemia (reduced CO-binding capacity).

Question 14

How does cardiac output affect TLCO?

Answer 14

Low cardiac output decreases TLCO.

Question 15

How does KCO change with age?

Answer 15

KCO increases with age.

Question 16

Which surgical lung reductions cause an increased KCO but a normal or low TLCO?

Answer 16

Pneumonectomy or lobectomy.

Question 17

Which musculoskeletal conditions cause raised KCO with reduced TLCO?

Answer 17

Scoliosis and kyphosis.

Question 18

Which neuromuscular conditions cause increased KCO despite reduced TLCO?

Answer 18

Neuromuscular weakness (reduced alveolar volume, preserved perfusion).

Question 19

Which inflammatory spinal condition increases KCO with reduced lung volumes?

Answer 19

Ankylosing spondylitis.