Slide Review or Manual Diff?
The CPT code 85004 (Blood count; automated differential WBC count) has many variations, each of which is charged instead of 85004 and including the work. These codes can be distinguished in the CPT code book, because they are indented. Examples:
- 85007 (blood smear, microscopic examination with manual differential WBC count)
- 85008 (blood smear, microscopic examination without manual differential WBC count)
In other words, performed a manual differential if a CBC with automated differential is performed is not billable in addition to the code 85004. All of these are “bundled” into 85004. Neither is a slide review, a spun hematocrit, or an automated reticulocyte count. All are considered iterations of a blood count with an automated diff, recognizing that the term “CBC” encompasses variations.
One of which is: should you reflex to a slide review or a manual differential?
The consensus rules from the ISLH (International Society for Laboratory Hematology) suggest the former. A slide review is a targeted review of a peripheral smear specific to the particular parameter or instrument flag. For example, a white blood cell count of >30 thousand reflexes to a “slide review” if it is the first time or a delta check failure within 3 days. That slide review logically involves checking for abnormal cells or cells that suggest a leukemoid reaction. A manual differential is necessary only to enumerate abnormal cells.
The slide review concept is an attractive idea in many ways: it takes advantage of technologist judgment, targets a review based on accurate instrument readings, and avoids the busy work of just reflexively banging out a 100-cell diff that may not add value to the report.
More significantly, a slide review reinforces what we already know: the instrument is much, much more accurate that we can ever be. Performing a manual differential to “prove” the instrument count is OK leads physicians down a path that doesn’t trust our technology. Performing a slide review sends the message that we are using the instrument to guide our workflow and look for abnormalities.
In my experience that’s been an easy sell for docs but much harder for staff. Almost all the techs I’ve known have had a knee jerk reaction that a slide review is more work. Why?
For one thing, after performing thousands of manual differentials it becomes second nature. It is comfortable, familiar, and repetitiously easy. Having said that, what is the first thing we all do when we finish? We compare the numbers to the automated differential. We might even repeat the manual differential if we think the numbers don’t match, which is really nutty behavior when you think about it. This begs the question, “What are we really doing?”
This could just be the shock of the new. We have to use new technology to change our diagnostic techniques. As suggested by the ISLH, part of this is slide reviews designed to look for what the instrument suggests. But can we teach old techs new tricks?
NEXT: Justifying Staff