Blood and Bone Marrow
Lymph node and other organ aspirates
Aspirate onto slides, or into an EDTA tube with NO added fluid (i.e. don’t add saline). If you aspirate onto slides and want to confirm that you have a good sample, the slides can be stained and still used for PARR.
- Send fluid in EDTA, or on a slide, either a smear or cytospin. If you aspirate onto slides and want to confirm that you have a good sample, the slides can be stained and still used for PARR.
- Multiple cytospin preps are the best sample (stained or unstained). An EDTA tube can also be sent. In order for the sample to be diagnostic we estimate you need 50,000 cells. Therefore if the CSF has a white count of 100, we need 0.5 mls of fluid, or the cells from 0.5 mls spun onto slides.
A note about non-diagnostic samples:
Non-diagnostic samples are obtained when there is too little DNA, or when there is an inhibitor of the PCR reaction. In the case of non-diagnostic samples, we will repeat the assay under conditions that eliminate the effects of the inhibitor1, but if that is not successful we will assume there was insufficient DNA. You will be charged for non-diagnostic samples even if we are unable to obtain a result, so please be sure your samples are cellular. When possible, we try to contact the submitting clinic if we think the sample isn’t going to be diagnostic, but this isn’t always feasible.
1You’re probably wondering why we don’t use these conditions all the time? There are several ways to manage inhibitors in PCR reactions, and they are all very expensive. Since we only rarely obtain non-diagnostic samples, we keep costs down by only using these methods when necessary.