Calculated Hemoglobins

No statement as such, but the result is filed in the LIS specifically as a calculated hemoglobin, completely separate from where a measured hemoglobin displays in the LIS.  The assumption from there is 'buyer beware'!

We add a disclaimer comment to the hemoglobin result from the epoc.

Do you mind sharing your disclaimer?

Our comment for the calculated Hemoglobin on the epoc:

Calculated Hb results are for screening and trending uses. Actual Hb measurement by the Lab should be used for Transfusion decisions.　

Thanks!!

Tierra,

The nurses are taught that the ISTAT is only used for tracking and trending.

I do not have to place anything in my policy because the Blood Bank has it in theirs. (If no CBC on file....no blood unless emergency release is what it boils down to.)

Deanna Bogner

We have the following comment attached to the HGB & HCT for all I-STAT results:

"ISTAT methodology for Hgb and Hct produces results less accurate than conventional laboratory methods. ISTAT Hemoglobin and Hematocrit results may vary from those of laboratory methods by up to 2 g/dL (Hgb) and by up to 4% (Hct). Interpret results carefully and in correlation with overall patient condition."

Wow, that's a significant disclaimer (I totally agree with it, however), but it does beg the question should you report it at all?  Especially when HIS systems often end up embedding LIS disclaimer commentary like this, making it often the case that a physician never ever sees it. 

Only asking because I wrestle with the notion of turning off the parameter altogether, because it is consistently a trouble spot - usually initiated by a call from a clinical unit saying 'is this machine broken - I did not get a result that matches the lab'  lol

James,

If it were up to me, I would love to not report the H&H on the i-STAT. Unfortunately taking things away tends to make providers upset...I really wish that they had chosen to not report it from the beginning.

Luckily I have a 'smallish' group of operators that use the i-STAT: Perfusion services, Anesthesia, and Respiratory. They have been trained to understand that they should use the i-STAT H&H for trends, not for making decisions about whether or not to transfuse.

I hear ya.  I worry about those type areas in particular though, because that seems to be where the discrepancies most often show up - critically ill patients with off-kilter plasma protein levels, receiving lots of IV infusions - I think that wreaks havoc on any conductivity-based H&H readings.  Speaking just for my facility, we had too many near-misses with discrepant values and we moved them to devices that measure hemoglobin directly.

  If you're ever interested, Radiometer has a good webinar about the value of measured hemoglobin specifically in those settings.  Of course, it's also a selling point for their equipment, but they do make some irrefutable points about conductivity-based H&H.  If you ever need the extra justification to pull the plug on reporting the iSTAT values...

I'll have to check that out, James. We are in the process of validating our new Radiometer ABLs for our new lab so that's good timing.

We use iSTAT, I don't see any disclaimer from Abbott on Hgb results.  Is there something I'm missing?

No, you're correct - I don't think Abbott admits to any consistent inaccuracies with regard to calculated hgb (of course); I think most everyone in this thread was simply reporting the reality of what they've observed at their facilities on actual patients, and therefore the precautions they've adopted.

Most inconsistencies I see with Hgb and Hct have to do with sample handling; failure to mix appropriately.  Abbott clearly states that a low Total Protein will affect results, making them falsely low.  So patients in the OR are particularly affected since massive IV fluids are infused; thus the CPB option in place for patients on by-pass to compensate.  We currently have the Sysmex and the "rule" of Hgb X 3 does not apply to the Hct, rather it is measured, so the Hgb do not match very well.  But the iSTAT Hct typically does match the Sysmex as well as to the spun Hct.  We do not have specific guidelines NOT to transfuse off of iSTAT but Blood bank does I believe recommend using CBC results.  Ivy