Specimen "available quantity" questions

[srikanth_adiga]

We are trying to understand how everyone currently uses the available quantity field of specimen.

The way it currently works is:
a. There are two fields. “Initial quantity” and “available quantity”.
b. To start with, “available quantity” is same as “initial quantity”
c. When a specimen is aliquoted or distributed, the “available quantity” is automatically reduced.
d. When a derivative is created, the parent specimen’s “available quantity” is NOT changed.
e. The “available quantity” field can be directly edited in the specimen page.

The current behaviour raises the following questions:

1. Does the “available quantity” field accurately display the quantity of the specimen? Especially since #d and #e above.
2. When a derivative is created, should there be a field to record “how much of the parent was consumed?”
3. Should the available quantity be editable? Or should be recorded as a “specimen event” where reasons why the quantity is being altered is recorded.

Thanks,
~Sri

Edited: To remove “dispose specimen during derive” since it is already supported and will be supported in OS v20.

[pgovindrao]

Another feature that might be useful is:
If user enters how much parent was consumed during aliquot/derived, system should record it as part of automatic events - derivative and aliquot event. That way it keeps track when and how much of the parent was utilized.

Thanks,
Poornima

[Rachel_Jewell]

Response to Sri-

1. Most of the time, yes. However, we’ve noticed that CaTissue doesn’t like decimals as much as whole numbers. For example: we receive 4 aliquots of serum at 0.8mLs each. The total amount received (initial qty and available qty) would be 3.2mLs. When you record that you received 3.2mLs as the initial qty (which updates the avail qty), and then you go to create 4 aliquots @ 0.8 mLs, the system will only let you create 3 of those aliquots as it states “There is not enough avail qty to complete request”. We have to up the initial and avail qty’s to 0.9 and then it will allow us to aliquot all 4 samples at the 0.8mL volume. However, then the initial qty is incorrect as it states we received a bit more than we actually did, but the avail qty states “0”. So zero doesn’t actually mean zero in CaTissue. In this case it means 0.1, but it doesn’t show the decimal.

Furthermore, most of the time we do not want the parent’s avail qty to change. It depends on the sample type though. For fluid, we may want it changed as usually you take a whole blood tube of XmLs, spin, and isolate samples from it, and then the whole blood is gone which means you’d want the avail qty to be 0. However with a tissue block, these are never depleted. So even though you might make derivatives or aliquots of slides or cores from this block, the block still exists and so you’d want the qty to stay the same. The only time you’d want the avail qty of a tissue specimen to turn to 0 is when it’s distributed and no longer in your bank. That would show that you do not have it in your bank. OR if the sample is actually depleted/scant and you cannot cut anything from the block anymore. This could constitute having the avail qty as 0, and more than likely we’d add a comment stating that the block is depleted/scant. We would also mark the status as “closed” since it’s unusable.

2. I don’t see how this would be useful for us as, like I explained above, usually for fluid parent samples, which are usually whole blood samples or at least a derivative of serum/plasma, the lab will be isolating or aliquoting those samples out and the parent and/or derivative will no longer exist as the children are the only samples that remain from that parent sample. We still need to record and keep the initial qty of the parent so we know how much of that parent was originally received, however avail qty could be updated to 0 since it no longer exists.

3. I think the initial and avail qty fields should remain editable. Sometimes we have to adjust this currently if mistakes are made and we need to show what is left or aliquot out extra.

Response to Poornima-
This would actually be a nice feature, mainly for when we complete distributions to researchers. We have to pull aliquots of serum/plasma and then thaw and re-aliquot the samples into smaller or larger increments (per whatever volume the researcher wants). Sometimes all of the aliquot is used, and sometimes there is a bit left over. Although I don’t see this being used for parent samples, it would definitely we used for aliquot samples within our group.

[pgovindrao]

Thanks for the explanation @Rachel_Jewell. We will log an issue for decimal quantity issue you have pointed out.

We will keep the available quantity editable.

Thanks,
Poornima

[srikanth_adiga]

@Rachel_Jewell The thing about available quantity and initial quantity is how tightly you want to control, audit and validate the data.For example, would you want to take a specimen and say how did it go from 10ml to 2ml, when there are only 2 aliquots of 1ml each? We might be able to get the data from audit data, but not everyone has access to audit data and it could be complex/time consuming.

OR if someone edits the initial quantity from 10 to 20, should the available quantity also increased by 10?

Its all about how tightly system should be regulated. I am not saying it should not be editable. Maybe whenever the quantity is edited, it should ask for “reason for change”.

~Sri

[Rachel_Jewell]

I like the “reason for change”. That could be saved as an event or something to track why it was changed. I think our system currently increases the avail qty if one manually increases the initial qty. We have to do this sometimes when a specimens initial qty isn’t recorded correctly. In this case though, the reason for change could be implemented. This may need more discussion though, maybe with other users inputs. I’ve never used audit data before, that I know of, so not sure how that works.

Thanks, Rach

[Matthew_Marcetich]

Responding to @srikanth_adiga 's initial post:

1. Available quantity should accurately display the quantity of the specimen. We have received feedback from some of our users recently that they would like an alert when available quantity of a specimen falls below a specified value.
2. I think this would be helpful.
3. I think having the available quantity editable would be helpful for our users, though it would be good to have as accurate of an audit trail as possible (especially for CAP labs). I think recording a reason why the available quantity is being altered would be a good thing.

[Matthew_Marcetich]

Additional feedback: some users are also interested in receiving an alert when a specimen’s collection volume is less than anticipated. Prompting for documentation when collection volume is less than anticipated might also be helpful.

Note: During demonstrations, users have sometimes found “count” and “quantity” ambiguous. When the difference was explained, users thought units for quantity would be helpful.

[srikanth_adiga]

Thanks @Matthew_Marcetich. We will review these comments and include in the v2.x roadmap.

~Sri