Educators face the issue of limited resources, so Medical Laboratory Science schools are able to illustrate only basic coagulation concepts in the student lab. George monitors the MLS Educators’ list, CLSEDUC, and came across this helpful suggestion from Program Director Michele Harms, MS, MLS. Michele gave me permission to reproduce the message and her laboratory procedure, attached at the end.
We do tilt-tubes in our student lab. The students actually enjoy these labs since they can see the clot form and love it when their tests in duplicate match perfectly. The student eye is not as fast as an instrument, so students may have slightly longer results, by a second or so.
For the mixing study lab, I use factor deficient plasmas that I re-label as patients. You could just use a heparinized sample, just don’t allow the 1:1 mix to incubate or it may act like an inhibitor. After performing a prothrombin time (PT) and activated partial thromboplastin time (PTT, APTT) with controls, they mix the patient specimen with pooled platelet poor plasma (PPPP). They run the PPPP in a 1:1 mix of patient and they see the correction, proving a factor deficiency.
Since I use factor-deficient plasmas, my students then utilize the labeled factor-deficient plasmas as reagents to mix 1:1 with their patient to discover which factor is missing. No correction = found the deficient factor. If you use a heparinized sample, you won’t have just one factor missing, so you won’t be able to do this part of the lab. The students utilize their coag pathway to determine if the missing factor is from the intrinsic, extrinsic or common pathway so they aren’t blindly picking reagents.
I also give them a brief case study on their patient, so they also know if it is a clotting or bleeding issue and the possible inheritance of the deficiency. Some of the case studies give away the disorder (clotting for XII), but they still have to prove it and they love when they get it right.
Here is Michele’s procedure: M Harms Mix Studies