"Out, Damn'd Spot!, Out I Say" - Blood Detection


This lab will demonstrate the very simple Kastle-Meyer test to determine the presence of hemoglobin expected in blood.


"Out, Damn'd Spot! Out I Say."

So sayeth Lady Macbeth in true Shakespearean fashion in Macbeth (Act 5).

But how did she know the spot was blood...unless she put it there!?

At a crime scene we expect to see blood stains and we're certain that the dark brown spots are indeed blood. but, we dare not say so, until we have completed a presumptive field test. With the ever presence of cell phone video recording, a simple comment ("did you swab those blood stains") can be argued in court that the technicians were not unbiased in their task performance.

We have a simple, inexpensive field test that will confirm that a stain or spot is blood- although not necessarily human blood. That analysis is best completed as a confirmatory test in the lab.

Lesson Times

One period
55 Minutes

Industries / Subjects / Grades

Industries / Pathways
  • Public Services Public Services
    • Legal Practices
    • Public Safety
K-12 Subjects
  • Science
    • Chemistry
Grade Levels
  • 10
  • 11
  • 12
  • Adult

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