Blood Typing Lab

Name_____________________________________ Block__________________ Date_____________________ Forensics Mystery Blood type Lab Scenario Police are called to a house where they discover a body near the endorse door. There is a fresh pool of stemma by the victims head. Officers question the neighbors and get wind that a plumber and an electrician made service calls to the house just hours before. They were able to trace both. They domesticise a shirt with a dark spotlights from the service van of the plumber and rags with similar dark stains from electricians van.Your forensics lab receives the following items to test savour 1 Stained cloth from plumbers van Sample 2 Stained cloth from the electricians van Sample 3 Blood collected from under the victims head Test Background The phenolphthalein test is a highly sensitive, being working capitalable of detecting ancestry spots practically invisible to the eye. In an certain criminal case, a positive phenolphthalein test would be followed by tests to gibe the species that produced the argumentation and if these tests indicate the personal line of credit is human, by tests to determine ABO, Rh and other business groups.There is no point in pursuing write and species identification procedures if the phenolphthalein test is negative. The phenolphthalein test is not absolutely specific for blood because most plants and some tool cells can also cause a positive reaction. Discussion Questions 1. Does a positive phenolphthalein test excavate that a stain is caused by blood? 2. Does a positive phenolphthalein test prove that a stain is caused by human blood? Procedure 1 1. Test the shirt and rags to determine if the stains are caused by blood. 2. Place a drop of phenolphthalein/peroxide solution on separately stain. 3.Observe if a color agitate occurs. A purple-violet color reaction indicates that blood (heme) is stick (positive reaction). Absence of this reaction indicates that blood is not present. 4. m emorialise your results Color reaction for Sample 1_________________________ Color reaction for Sample 2_________________________ Based on the results of this test, which person, the plumber or the electrician be throw ins your prime suspect? ____________________________________________________________________________ Additional Information When confronted, your chief suspect claims to rescue a nosebleed, thus accounting for the blood stain.Investigators have now been able to recover a blood sample (Sample 4 ) from the suspects van. It is suitable for blood typing. You ask and receive a blood sample from the suspect (Sample 5). Proceed to Procedure 2. Test Background Blood groups are created by molecules present on the surface of red blood cells. The table shows the four ABO phenotypes (blood groups) present in the human population. When red blood cells carrying one or both antigens are exposed to the corresponding antibodies, they attach that is, clump together.People usually hav e antibodies against those red cell antigens that they lack. The ABO Blood Groups Blood Group personnel casualty Cell Antigen (Protein on blood cell) Serum Antibody (Produced by Body) A A Anti-B B B Anti-A AB A and B Neither O Neither Anti -A and Anti -B Discussion Questions 1. How do you determine a persons blood type? 2. Can a persons blood type prove or disprove that he/she committed a crime? How? Procedure 2 1. Add a drop of synthetic anti-A (blue) to the well labeled A. Replace cap. . Always replace the cap on the vial before opening the next vial to prevent cross contamination. . Add a drop of synthetic anti-B (yellow) to the well labeled B. Replace cap. 3. Add a drop of synthetic anti-Rh serum (clear) to the well labeled Rh. Replace cap. 4. Using the dropper vial, place a drop of Sample 3 (the victims blood) in separately well of the blood typing slide. DO NOT stir up THE WELL 5. Replace the cap on the dropper vial. 6. Using a different color blend stick for each well (bl ue for anti-A, yellow for anti-B & white for anti Rh), gently stir the synthetic blood and anti-serum drops for 30 seconds.Remember to discard each mixing stick after a single use to annul cross contamination. 7. WAIT 60 Seconds. 8. Carefully examine the thin postulates of liquid mixture left behind. If the film remains uniform in appearance, there is no agglultination (no clumps, negative reaction). If the film as clumps, agglutination has occurred (positive reaction) 9. mark blood type of the sample using the data table below. Answer yes or no as to whether agglutination occurred in each sample. A positive agglutination reaction indicates blood type. 10. Record the results for each blood sample in the data table.Data Table Sample 3 Sample 4 Sample 5 Anti-A Anti-B Rh Blood type 11. Then repeat steps 1-9 for Samples 4 and 5. Record each results on table. 12. Thoroughly rinse the blood typing slides and return all materials. Conclusion Based on your results, did the b lood collected from the suspects van come from the suspect? ____________________________________________________ Could this blood have come from the victim? ____________________________ What can you conclude from your results? (Remember to cite your data). __________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ _____________________________________________________________________ _________________________________________________________________________________________________