12

10

 8

 6

 4

 2

 0

6

5

4

3

2

1

0

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6

TIME (sec) VOLUME (L) (BTPS)

L (B

V

O

L

U

M

E ( ) T

P

S)

F

L (L ) (B

T

P ) O

W

S/ S

Sharp peak 

Smooth curve

Smooth descent

 to baseline

Flat (plateau)

before 15 seconds long

Steep climb 

Vertical 

 rise

Hesitation; Slow Start; Large Extrapolated Volume

Delete Curve; Coach: Blast FASTER

Cough in First Second

Delete Curve; Correction: Try a drink of water

6

5

4

3

2

1

0

6

5

4

3

2

1

0

12

10

 8

 6

 4

 2

 0

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 1 2 3 4 5 6 0 1 2 3 4 5 6

TIME (sec) VO TIME (sec) LUME (L) (BTPS) VOLUME (L) (BTPS)

U (B

P ) V

OL M

E (L) T

S

U (B

P ) V

OL M

E (L) T

S

FL (L S/ ) (B

TP O

W

S)

FLO

W (L S/ ) (B

TPS)

Peak shifted

to right

Slow take off

Curve dips

Curve dips

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Delivering on the Nation’s promise: Safety and health at work for all people through research and prevention.

N SERVICES

MA

USA

UH & HTLAEHF OTNE MTRAPED

U.S. Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health DHHS (NIOSH) Publication No. 2011-135

Extra Breaths

Correction: DELETE CURVE; Use nose clips and lips tightly sealed

TIME (sec) VOLUME (L) (BTPS)

V LU

M

E ( ) (B

T

P

S) O L

FL ( / ( S) O

W L S) B

TP

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6

Extra

breaths

6

5

4

3

2

1

0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

1 or more extra breaths

look like miniature

additional curves

Extra breaths

Poor Initial Blast

Coach: Blast air out HARDER

6

5

4

3

2

1

0

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 1 2 3 4 5 6

TIME (sec) VOLUME (L) (BTPS)

U

B

P ) V

OL M

E (L) ( T

S

FLO

W (L S/ ) (B

TPS)

Rounded or

flat peak

Slow climb

Partially Blocked Mouthpiece

Coach: Position mouthpiece between teeth and

on top of tongue; secure dentures

6

5

4

3

2

1

0

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 1 2 3 4 5 6

TIME (sec) VOLUME (L) (BTPS)

) V

OLU

M

E (L) (B

T

P

S

( FLO

W (L S/ ) B

TPS)

Smaller peak

and curve

wobbles

Curve wobbles

Leak

Correction: Check equipment and connections

6

5

4

3

2

1

0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 1 2 3 4 5 6

TIME (sec)

VOLUME (L) (BTPS)

V

OLU

M

E (L) (B

T

P

S)

Curve

moves

backwards

Curve drops down

Glottis Closure or Breath Holding

Coach: Initial BIG BLAST then RELAX and keep blowing

6

5

4

3

2

1

0

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0 1 2 3 4 5 6

TIME (sec) VOLUME (L) (BTPS)

V L M

E ( ( T ) O

U L) B

P

S

L ( T ) F O

W (L S/ ) B PS

Drops straight

down

Abruptly flattens

Incomplete Inhalation

Coach: Take a DEEPER breath

6

5

4

3

2

1

0

12

10

 8

 6

 4

 2

 0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6

TIME (sec) VOLUME (L) (BTPS)

U

M

E L B

P ) V

OL ( ) ( T

S

FLO

W (L S/ ) PS) (B

T

Gap

Gap

Curves have same shape

but are different sizes

Inconsistent Effort

Coach: One continuous blast and keep blowing

0 1 2 3 4 5 6

VOLUME (L) (BTPS)

Curve

 flattens out

Curve tilts

6

5

4

3

2

1

0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

TIME (sec)

V

OLU

M

E (L) (B

T

P

S

D )ifficult

to see

on this

curve

Does not flatten

for 1 second

No Plateau Before 15 Seconds

Coach: Keep blowing until told to stop

6

5

4

3

2

1

0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

TIME (sec)

(L T ) V

OLU

M

E ) (B

P

S

12

10

 8

 6

 4

 2

 0 0 1 2 3 4 5 6

VOLUME (L) (BTPS)

F O

W (L S) T

P ) L / (B

S

A Valid Test has:

3 or More Good Curves

and Repeatable FVC and FEV1*

Get Valid Spirometry Results EVERY Time

Green = Good Curve

Red = Error

HOW TO CORRECT TEST ERRORS

Negative Zero Flow Error

Correction: No airflow through sensor when spirometer zeroing

Hold sensor upright during test

TIME (sec) VOLUME (L) (BTPS)

U

B

P ) V

OL M

E (L) ( T

S

FLO

W (L S/ ) (B

TP ) S

Curve ends

early

OR Curve drops down

8

7

6

5

4

3

2

1

 1 2 3 4 5 6 7 8 9 

14

12

10

8

6

4

2

0

1 2 3 4 5 6 7 8

Difficult

to see

on this

curve

Positive Zero Flow Error

Correction: No airflow through sensor when spirometer zeroing

Hold sensor upright during test

TIME (sec) VOLUME (L) (BTPS)

V LU ) (B

P ) O

M

E (L T

S

L ( ( PS F O

W L S/ ) B

T )

Flat line

extends

to right

Continues to climb

NEVER flattens

–

O L S) S) FL W ( / (B

TP