Microcrystalline Test

Christopher, Crystal,Justin, & Jimmy

How It Works

They are used as a confirmatory testo They detect whether or not a sample

is/contains blood and it not actually something like red paint or ketchup

o As opposed to a presumptive test which indicates the POSSIBILITY that the substance being tested for is present

Two Types of Tests The two tests that fall under the category of a

microcrystalline test are known as the TAKAYAMA test and the TEICHMANN test

Takayama Crystals

Takayama Test This test determines if the substance in question

is blood. The Takayama Test was used to determine if

there was blood on the coat of a soldier from the Way of 1812.

It works by gently heating heme (dark red, non-protein, iron-coating part of hemoglobin, C34H32FeN4O4) and adding it to pyridine (C5H5N) when there is some kind of sugar present, such as glucose, in order to create pyridine ferriprotoporphyrin crystals.

This test produces brown crystals.

Takayama Reaction and Crystals

Takayama Reaction Takayama Crystals

Teichmann Test This test determines if there is blood present on

suspected dried blood stains. The hematin crystals begin to form when heated

blood is mixed with glacial acetic acid where there is salt.

The positive result is caused by the combination of a halogen with ferriprotoporphyrin (red-brown to blue-black crystalline salt containing iron).

This test produces pink crystals that can reach up to 10 micrometers in size.

Strengths The amount of time the bloodstain has been dry

does not affect the formation of the hematin crystals.

Twelve year old stains are capable of giving a positive result when tested by the Teichmann.

Bloodstains over 20 years were also able to give a positive with this test.

The sensitivity and specificity of the Takayama and the Teichmann tests are similar: both give positive results with as little as 0.001 ml of blood or 0.1 mg of hemoglobin.

Weaknesses While Teichmann crystals may not form with

stains from materials such as leather, older stains have been reposted to give false negative results when tested with the Takayama Reagent.

These tests are less sensitive than other tests. The outcomes (+) and (-), (+) means the sample

is blood but the test won’t tell from what species the blood is from.

Example Case #1The body of a 27 year old was found in a wooded picnic area. Investigators searched the area and

found what appeared to be a red substance near a picnic bench. Hoping it was going to be helpful in the investigation, they sent a sample to a forensics

lab where they did a Takayama test. Results showed that the substance was not blood and was

ruled out as part of the crime scene.

Example Case #2Murder suspect, Carlos Ramirez’s trunk was

searched and in it, a red stained T-shirt. Investigators sent the stained clothing to a

forensics lab where they performed a Teichmann test on it. Results show it was in fact blood and was

sent on for further testing.

Real CaseState VS Allen

On 16 February and 2 March 1998, the Durham County grand jury returned bills of indictment charging Defendant with first degree sex offense, felony child abuse, and first degree murder.

Scientists performed a Teichmann test on the victim’s training pants, underwear, and sleepers. All came back negative

Review Questions1. What is the purpose of a microcrystalline test?

2. One strength of this test?

3. How much blood is needed to be detected by this test?

4. What color crystals does the Takayama test produce? The Teichmann?

To test for the presence of blood.

It can detect the presence of blood in stains over 20 years old.

0.001 ml of blood or 0.1 mg of hemoglobin.

Takayama: brown crystals. Teichmann: pink crystals.

Works CitedBell, Suzanne, Barry A. J. Fisher, and Robert C. Shaler. Encyclopedia of forensic

science. Rev. ed. New York, NY: Facts On File, 2008. Print.

 "Blood Identification." what-when-how — In Depth Tutorials and Information. N.p., 1

Nov. 2010. Web. 3 Apr. 2013.

<http://what-when-how.com/forensic-sciences/blood-identification/>.

James, Stuart H., Paul Erwin Kish, and T. Paulette Sutton. Principles of bloodstain

pattern analysis: theory and practice. Boca Raton, Fla.: CRC, 2005. Print.

Giannelli, Paul C. Scientific Evidence. N.p., 2012. Web. 2 Apr. 2013.

<http://www.americanbar.org/content/dam/aba/publications/criminal_justice_ma

gazine/sp12_sci_evidence.authcheckdam.pdf>.

Klinkosum, Mike. North Carolina Bar Association. N.p., 29 Sept. 2010. Web. 2 Apr.

2013.

<http://criminaljustice.ncbar.org/newsletters/truebilloctt10/statevgregorytaylor

>.