Do you need to have a seriously abnormal blood draw to see anything wrong in bone marrow as well?

September 17, 2009 5:58 PM

hematologyfilter: Confused about what (and when?) you can determine from a bone marrow tap, & platelet count

I know there's been other mefi threads on platelets and blood count and iron supplements (not that that affects platelet count, as I understand it) but i did not find the answer to my particular question there. I've been going to various doctors for many months now trying to diagnose a new mystery ailment, they've taken tons of blood samples, and so far little progress has been made. I know for certain I've already got Hashimoto's, which I've had for years, and IBS/celiac (I've had every GI test there is, pretty much, as well - everything looks good in the GI, they can't see a bleed anywhere).

And I know Hashimoto's & celiac make me prone to other problems, potentially.

I went in in Dec of last year complaining of being super fatigued from trying to climb stairs and doing aerobic exercise.. still have it. Sleep has been getting more and more erratic, I suspect mostly from increasing depression/anxiety (so I did a sleep study), and I'm also considering trying to alter my thyroid medication to see if that has a useful effect.

However, one thing they've all noticed is that I've been anemic - ferritin started at around 12, went down to 6, and after taking about 6 months of Floradix at the regular dose, I've managed to hover at around 17-20 (I tried taking generic iron capsules from Whole Foods, and while they did constipate me, they did nothing for my iron count), and platelet count has been slowly decreasing, starting around 140ish and most recent count yesterday was 111.

However, about 3 weeks ago, the platelet count seemed to jump up to 138. This would lead me to believe that either the downward trend for platelets during this period of time means something - or nothing. Or it's a lab error. I know that it hasn't been dangerously low.. in fact if I had just had a regular single checkup with a slightly low platelet count and had otherwise been feeling ok, I would have likely just waited till my next checkup or two and ignored it.

But the reason I went to the hematologist is that all these docs kept recommending that I go because of the fatigue the anemia seems to have brought on, and the seemingly progressively lowering platelet count.

Anyway, the blood doc says now that since the platelet count seems to have vacillated, he is not going to recommend a bone marrow tap at this time, but to come back in another 4 months and recheck the labs. If I want to do one now he'll set it up, but he doesn't "think we'll be able to see anything."

Now my knowledge of blood disorders is pretty limited, but I was under the impression that if there was something seriously jacked up with your blood, you'd see it by looking at a bone marrow draw whether your blood was measuring abnormally or not - and that ordinarily, you just wouldn't go checking there during a 'regular' checkup if you are otherwise healthy willy-nilly, because it's invasive and hurts and who the hell wants regular bone marrow taps if they don't need them?

So what's the deal? Do typically clear indicators of things like leukemia or other serious blood disorders only appear in the marrow if your blood counts are way "off the chart" wack?

posted by anonymous to Health & Fitness (3 answers total)

I think you may sort of be misinterpreting what your doctor was implying. It's not that things have to be bad in the blood before the marrow is useful. As you suspect, the opposite is usually true and the peripheral blood can be relatively unremarkable but you might still have a blood cell disorder. Typically the gold standard for evaluating most any hematological issues is in fact looking at the bone marrow but in some situation the bone marrow is unlikely to yield any additional helpful information to what your peripheral blood has already demonstrated. You may be in such a situation. For example, perhaps he believes that you are so unlikely to have a leukemia or other intervenable disease process only captured by biopsy, that the risks of putting you through biopsy outweigh the benefits. This is entirely conjecture however, and you should ask him specifically what he thinks about your particular case, and why he doesn't think the biopsy would be helpful.

Incidentally, if you do indeed have celiac, anemia is an incredibly common manifestation, but some patients also do develop (typically mild) thrombocytopenia (low platelets). See here.
posted by drpynchon at 7:10 PM on September 17, 2009

A bone marrow biopsy would show things like:
leukemias of all varieties
some lymphomas
myeloma (usually)
myelofibrosis
myelodysplastic syndromes
as well as giving supportive information to a few other problems.

The real purpose for a bone marrow biopsy is to find bone marrow disease. Which is almost always reflected in the peripheral blood. so yes, typically the marrow will be pretty normal unless the blood counts are showing a problem. Early disease can be found in the marrow before it shows in the blood, but you really don't gain anything by just doing random marrows on people with normal blood counts.

The symptoms that you are describing really don't point towards the marrow. Aside from the drifting platelets there is nothing there to indicate a primary bone marrow problem. And the platelets are really not too far out of whack. You don't mention how bad the anemia is, but if your docs think it is an iron deficit, then go with that. I have seen hemoglobin as low as 6 and 7 because of iron deficiency.

Don't go for the marrow unless your hematologist really wants it.
posted by SLC Mom at 8:40 PM on September 17, 2009

Both drpynchon and SLC Mom make absolutely strong points.

An additional point is that a bone marrow draw hurts a lot and there can be complications associated with it. If there isn't a pressing reason to do one, it kinda sorta hovers around the "do no harm" hypocratic oath thing.
posted by porpoise at 9:57 PM on September 17, 2009