Research Questions regarding the interaction of blood and fabrics

Addendum to: Interaction of Blood and Fabrics Research Needs Assessment Form

OSAC BPA Subcommittee March 1, 2021

Page 1 of 3

ADDENDUM

Research questions regarding differentiating spatter from transfer for blood 

deposited on textiles

OSAC Bloodstain Pattern Analysis Subcommittee

March 1, 2021

Introduction

This document serves as an addendum to the OSAC Research Needs Assessment Form entitled 

“Differentiating spatter from transfer for blood deposited on textiles”. The BPA Subcommittee is 

of the opinion this addendum provides additional details not captured in said form.

This document proposes research topics that will provide valuable scientific data to underpin the 

interpretation of bloodstains and bloodstain patterns on fabrics, in particular clothing, and other 

textiles. 

Limited research indicates variability in the way blood interacts with different fabrics and other 

textiles, affecting resultant bloodstain appearance. The research thus far indicates the resultant 

bloodstain appearance is affected by:

1. Fiber type (e.g. manufactured or natural),

2. Fiber properties (e.g. absorbent v non-absorbent),

3. Fiber construction (e.g. filament or staple),

4. Yarn construction (e.g. twisted or non-twisted yarns),

5. Fabric construction (e.g. woven or knitted),

6. Fabric treatments (e.g. water-proofing, wicking enhancement).

What is the potential benefit for the Bloodstain Pattern Analysis discipline?

Fulfilling this research need would improve interpretations of bloodstains on fabrics. This would 

improve reliability and accuracy of interpretations and reduce discrepancies among analysts.

What is the problem? 

1. Blood ‘behaves’ differently on porous fabrics/textiles than it does on non-porous surfaces.

2. The interaction between blood and fabrics/textiles appears to be complex and is not well 

understood.

3. Great variability exists in the properties of fabrics/textiles, and this variability can 

potentially influence the appearance of resultant bloodstains.
Research Questions regarding the interaction of blood and fabrics

Addendum to: Interaction of Blood and Fabrics Research Needs Assessment Form

OSAC BPA Subcommittee March 1, 2021

Page 2 of 3

4. The relative importance of fabric/textile properties that significantly influence bloodstain 

formation and ultimately the interpretation of those bloodstains remains unknown.

5. Given this variability and complexity, straightforward answers to the research questions 

may not be easily obtained.

What are the research questions?

1. What factors affect the way blood interacts when it is deposited on fabrics/textiles? 

Questions to be considered for investigation include:

a. How does fabric/textile type influence the resulting bloodstain(s)?

i. What influence does construction have, e.g., weave, knit, texture, porosity, 

pigment/dye, etc. have on bloodstain formation and appearance?

ii. What influence do yarn properties, e.g., manufactured or natural, twist, 

thickness, absorbency, wettability and wicking properties, etc. have on 

bloodstain formation and appearance? 

b. How does the condition of the fabric/textile influence appearance of and the ability 

to interpret the bloodstain(s)?

i. What influence do fabric/textile treatments, e.g., stain resistant, fire 

resistant, water-proofing, fabric softener, starch, dry cleaned, ironing, UV 

protection, etc. have on bloodstain formation and appearance?

ii. What influence does moisture content of a fabric/textile, e.g., sweat, water, 

wet versus dry and other liquids, etc. have on bloodstain formation and 

appearance?

iii. What influence does washing, e.g., type of wash (hand, machine, dry clean) 

and number of washes, have on bloodstain formation and appearance?

iv. What influence does fabric history, e.g., fabric age, wear and tear, presence 

of dirt and/or grease, etc. have on bloodstain formation and appearance?

c. How do blood droplet volume, blood droplet velocity, kinetic energy, and angle of 

impact influence resulting bloodstain patterns?

d. How do blood volume, transfer pressure and movement influence resulting 

bloodstain patterns?

e. How does the presence of an underlying layer influence the resulting bloodstain(s) 

observed on the outer layer? 

i. What influence does the amount of stretch/tension in the fabric and/or 

underlying layer have on bloodstain formation and appearance?

f. How does the wearer’s motion/activity/folding of the fabric influence the resulting 

bloodstain(s)? 

i. Does area of origin apply to fabrics, in particular worn clothing, and other 

textiles?
Research Questions regarding the interaction of blood and fabrics

Addendum to: Interaction of Blood and Fabrics Research Needs Assessment Form

OSAC BPA Subcommittee March 1, 2021

Page 3 of 3

2. Is there a way to reliably distinguish between spatter and transfer stains when conducting 

bloodstain pattern analysis on fabrics/textiles? Questions to be considered for investigation 

include:

a. What bloodstain characteristics typically define transfer stains and do they apply to 

fabrics/textiles?

b. What bloodstain characteristics typically define spatter stains and do they apply to 

fabrics/textiles?

c. What bloodstain characteristics can be used to distinguish between transfer and 

spatter stains on fabrics/textiles?

i. How does the kinetic energy of a spatter droplet affect the subsequent 

spreading of the resulting bloodstain? Does it do so in a way that may be 

used to identify the origin as a spatter rather than transfer? 

d. What fabric/textile variables/properties influence the ability to interpret a 

bloodstain as spatter or transfer? 

e. How do fabric/textile variables influence the appearance of transfer stains when 

those stains are caused by other bloodstained fabrics/textiles?

f. Is the ability to distinguish between transfer and spatter stains more reliable on 

some fabric/textile types than others?

3. What factors affect the drying of bloodstains on fabrics/textiles? Questions to be 

considered for investigation include:

a. What fabric/textile properties influence bloodstain drying time? 

b. What effect does blood/blood droplet volume have on bloodstain drying time?

c. If the fabric is being worn at the time of blood deposition, what effect does the 

continued wearing of that fabric have on drying time?

4. Is there a way to reliably determine the age of a bloodstain deposited on a fabric/textile? 

Questions to be considered for investigation include:

a. How does the appearance of a bloodstain on fabrics/textiles change over time?

i. What fabric/textile properties influence the change in the appearance of the 

bloodstain as it ages?

ii. What environmental factors influence the change in the appearance of the 

bloodstain as it ages?

b. Can fabric/textile properties influence the clotting process?

i. Which fabric/textiles properties influence the clotting process and in what 

way?