Introduction: Hemident is a presumptive test that identifies the presences of blood. This test contains two reagents that are reliable and sensitive. Hemident Assay could provide results of a sample as small as one part per million. If blood is present there would be a colorimetric result of a blue/green color. It identifies mammal blood.

Materials: Fresh Plate Sharpee

Horse Sample Rack

Canine Sample Micropipette

Positive Blood Sample

Left Reagent

Right Reagent

Procedure: Obtain a fresh plate label it with title of the preformed lab, name and date a corner where it could be read. Place the sample name above the well where sample is intended to be placed.

- Obtain each sample and give a detail description of each sample. Provide measurements of each sample. Cut no more than 2mm from sample and provide the measurement of the cut from sample. After cutting a piece from each sample, place it into the matching labeled sample well.

- After placing each sample into the proper well, pipette 20 µL of the left reagent into each well first. Pipette 20 µL of the right reagent into each of the well last.

- Make note of the color change and how long it takes to produce the color change.

Questions:

1) What color is the leuco-based form of malachite green?

2) The leuco-based form of malachite green can be oxidized by the catalysis of

to produce a color.

Circle correct answer

3) Reaction of the hemident assay is carried out under acidic/basic conditions.