Cow blood - A superior storage option in forensics?

Area of Science:

• Forensic Science
• Hematology
• Rheology

Background:

• Modified blood products are used in forensic analysis.
• Drawing blood from conscious animals offers an alternative, but requires characterization.
• Existing data on cow blood lack comprehensive hematological and rheological perspectives.

Purpose of the Study:

• To investigate the hematological and rheological properties of cow blood during refrigerated storage.
• To assess the impact of storage on blood components and their suitability for bloodstain pattern analysis.
• To correlate changes in blood properties with passive drip pattern experiments.

Main Methods:

• Collected cow blood and subjected it to refrigerated storage.
• Analyzed hematological parameters and rheological properties (viscosity at high and low shear rates).
• Conducted passive drip pattern experiments on various substrates.

Main Results:

• Cow blood viscosity increased with storage, indicating reduced red blood cell flexibility without hemolysis.
• Storage minimally affected stain size across different substrates.
• A significant increase in low shear rate viscosity (up to threefold) was observed, correlating with increased satellite spatter.

Conclusions:

• Early changes in suspension properties, specifically viscosity, indicate storage lesion in cow blood, not hemolysis.
• Comprehensive rheological analysis is essential for detecting gradual changes in blood properties.
• Accurate forensic simulations require understanding these storage-induced rheological alterations in cow blood.