BLUESTAR® OBTI is the perfect complement to BLUESTAR® FORENSIC. This rapid screening test presumes that a bloodstain is of human origin. This helps the investigator to choose to collect or not a sample as evidence. A positive result indicates a strong likelihood for the presence of human blood. A lab analysis will later confirm or infirm this presumption.

BLUESTAR® OBTI is an evolution of Hexagon OBTI. Both products are identical in their formula, production site, quality and care given to their production, as stated in the confirmation note by the original design manufacturer Human GmbH.

BLUESTAR® OBTI is a two-part test: a collection tube for the blood sample, and a test bar.

A sample of the presumed human blood trace is transferred into the tube with transport medium. This mixture is added drop by drop to the test. A positive sample is typically detected within 2-5 minutes.

A single red line means the testing liquid is working fine but no human blood has been detected, two red/pink lines mean the test has detected human blood.

Principle

Human hemoglobin (hHb) in the sample reacts with a reagent consisting of red colored particles and monoclonal anti-human Hb antibodies. The immunocomplex migrates to the test zone where it is captured by an immobilized second antibody directed against hHb forming a pink test line to indicate a positive result. Unreacted reagents migrate further and are bound in a second line by immobilized anti-mouse lgC antibodies. This red control line indicates proper function and correct handling of the test.

The test detects whole blood up to a dilution of 1 : 2,000,000. As little as 250 red cells are required for a positive result.

The BLUESTAR® OBTI test, easy to read thanks to its red lines is capable of detecting 0.05 µg/ml hemoglobin and has a storage temperature up to 30°C.

False positives

The blood of the following animals did not react with the BLUESTAR® OBTI : cattle, pig, sheep, goat, rabbit, chicken, duck, goose, turkey, guinea pig, red deer, cat, dog.

Positive results were obtained with blood from primates (gorilla, and of some Mustelidae (weasel, badger).

Badger blood reacts weakly at concentration of 200 µg/ml. Horse blood reacts at concentrations above 500 µg/ml.

Therefore a positive result is not in itself an evidence of the presence of human blood, but it indicates a high probability of its presence.

Ordering BLUESTAR® OBTI

Box of 24 tests. Order code # HU-829

Each box includes 24 collection tubes and 24 tests.

Box of 6 tests. Order code # HU-830

Each box includes 6 collection tubes and 6 tests.