Clinical pathology question

[Histiocytosis X]

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Hi, guys. I'm an intern now and the hospital where I work reports CBCs to the hundredths decimal place (except platelets, of course). I understand that whatever they are measuring is true for that sample... I am just curious what the actual degree of certainty is over multiple samples. If a hemoglobin change from 8.12 to 8.10 is insignificant why even report it?

 

[KluverB]

Because we can.

 

[yaah]

I would suspect that there have been studies done that show that people reading reports tend to ignore the last digit, so reporting an extra one makes it seem more precise. Failing that though, the number is reported because that is where the accuracy lies. Just because it isn't significant whether something is 8.12 or 8.14 doesn't mean you can't report it that way. I don't know though. Do you ever read gross descriptions? People weigh large gross specimens like prostates and report the weight to the 1/100 of a gram. "Prostate weighs 46.22 g," for example. That is ludicrous but people still do it.

 

[Histiocytosis X]

The reason I wanted to bring it up is my med student keeps saying things like "hemoglobin is improving... Up from 10.79 to 10.83" and I thought it was funny. I did analytical chemistry before med school so I'm still somewhat keyed into measurement value and accuracy.

 

[TinyFish]

The reason I wanted to bring it up is my med student keeps saying things like "hemoglobin is improving... Up from 10.79 to 10.83" and I thought it was funny. I did analytical chemistry before med school so I'm still somewhat keyed into measurement value and accuracy.

Oh, that's really cute.
Sorry, I don't have anything of substance to contribute to this thread.

 

[lipomas]

The reason I wanted to bring it up is my med student keeps saying things like "hemoglobin is improving... Up from 10.79 to 10.83" and I thought it was funny. I did analytical chemistry before med school so I'm still somewhat keyed into measurement value and accuracy.

Those numbers are probably quite accurate. The problem is that the actual values in the blood sample are going to vary by more than that from hour to hour based on factors such as hydration status.