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FAQ for "How Are Antibodies Used for Blood Typing?"

Posted: Thu Sep 20, 2012 3:58 pm
by amyc
The following FAQ contains frequently asked questions and answers about the "How Are Antibodies Used for Blood Typing?" Project Idea and/or Project Kit ( ... l?from=AAE). If you are having trouble with the procedure, you may find assistance in the answers below.

Q: I can't tell if a reaction has occurred, help!
A: Make sure you have stirred the liquid for at least 30 seconds and not more than 45 seconds. You may need to let it sit for a few seconds after you stop stirring to see if any cloudiness or particles will form. The particles may be large and colored or colorless, or the liquid may turn cloudy with small particles. These both indicate a reaction has occurred. Look very closely at the liquid; look at it under different lights. Don't hesitate to repeat trials until you get consistent results; there is enough in the kit. You could try using two drops of blood sample and two drops of antiserum. Make sure the drops are at least as large as a pencil eraser. The final product may be clear/white or light or dark pink depending on the combination of blood and antiserum.

Q: The blood samples are slightly different colors. Is that normal?
A: Yes, that is normal; some of the blood samples will appear darker than others. This will not affect the final results. Remember that the "reaction" between antiserum and blood sample can be different colors. The important thing is if it turns cloudy or particles form (a precipitate).

Q: My results show all the same blood type. Is that right?
A: There must be a problem! The samples are not all the same, so if you're getting the same result for every sample, something must be going wrong! Read details on how to determine if a reaction has occurred, and reference the Figure 1 in the Procedure of the Project Idea. Repeat your trials at least 3 times, and you will hopefully begin to get consistent results.

Q: I'm getting different results each time. Why?
A: Make sure to properly rinse your well plates and stirring sticks between trials! Also remember that each antiserum has a corresponding stirring stick color. Make sure you are looking very closely at the wells to determine if a reaction has occurred. Make sure you are reading the blood type chart on the Project Idea correctly and that you are entering data correctly on the data table. Are your drops of sample and antiserum large enough? They should be at least as large as a pencil eraser, if not larger. Make sure to use equal quantities of sample and antiserum. One final piece of advice is be persistent and patient! Don't be afraid to do more than three trials until you get consistent results.

If you have other questions about the procedure or need assistance troubleshooting the "How Are Antibodies Used for Blood Typing?" Project Idea and/or project kit, please post your question in the forum at Ask an Expert: ... m.php?f=80. Our team of volunteer Experts is available to assist. We attempt to reply to questions within 24 hours. Please note that you will need a free Ask an Expert account in order to post questions.