Blood from the lung or upper airways may cause a stain as the victim forcibly exhales during respiration.
Source of blood - one or more of the following:
(1) lung
(2) trachea or bronchus
(3) mouth or oropharynx
(4) nares
Patterns of expiration that may impart more energy to the exhaled blood:
(1) coughing
(2) sneezing
(3) gasping
Features:
(1) The greater the force at exhalation the smaller the droplets. A forceful exhalation can generate a fine mist.
(2) Blood mixed with saliva will have a lighter color.
(3) Blood coughed from the lungs may contain small air bubbles.
(4) Expiratory blood stains may be mixed with stains from blood dripping from the mouth or nose.
Differential diagnosis:
(1) atomized blood from a high velocity gunshot
(2) high velocity splatter
To read more or access our algorithms and calculators, please log in or register.
Specialty: Clinical Laboratory