Is a low blood platelet count serious?
May 15, 2009 9:04 PM   Subscribe

What does having low blood platelets mean? I went for a check-up a couple weeks ago (it's only a few months before I reach the big 30) with a new doc. The doc I usually go to left my insurance company and the new one I was assigned was booked for months, so I just randomly found one to go to.) I was told everything checked out except my blood platelet count was 119, and that I need to come in and get re-checked.

I have no symptoms of anything, not fatigued, don't overbleed, nothing, feel the same. I'm okay, but my mother is not, she's kind-of freaking out and that's making me kind-of uneasy.

Should I be freaking out? I have no idea what's going on. This feels surreal to me. I've never had to get rechecked for anything, always had a clean bill of health. Even when a couple years ago I was told I had low blood or low iron or something, I was just told to take iron tablets, nothing like having to come back to get re-tested.

Can you help me gain some perspective on this? Thanks
posted by anonymous to Health & Fitness (16 answers total)
This is very common. Routinely we will see variations in white blood cells and platelets, as they are fairly dynamic, fluid cell lines and do change from day to day. I expect you'll be asked to repeat another CBC in a few weeks. Don't get worried,
posted by docpops at 9:13 PM on May 15, 2009

It's my understanding that thrombocytopenia is generally a marker of autoimmune disorders, including but not limited to HIV. It could also be an indicator of leukemia. Then again, there seem to be some rather benign conditions that could lead to it as well.

I don't know that it's time to freak out yet, but this is probably somewhat more serious than an iron deficiency. I would prepare myself for a possibly life-changing diagnosis.
posted by dhartung at 9:14 PM on May 15, 2009

I've had this ever since I've taken complete blood panels. Well over 10 years. No ill effects that I can tell so far, and my physicians never seemed concerned. And it's also 119. Further, Mean Platelet volume is too high at 14.1 (the upper range is 13fL).

The way my physician put it, unless it plunges much, much lower, odds are I do not need to "prepare myself for a possibly life-changing diagnosis" as dhartung put so alarmingly. Again, it's been over 10 years and so far so good, I think.
posted by VikingSword at 9:30 PM on May 15, 2009

dhartung - no offense, but I expect anon. can scare themselves shitless with a few clicks on Google. Let's try to keep things somewhat grounded.

A healthy person with a slightly low platelet (reference labs vary, but 140-150 is generally a normal lower limit) is not a clinical concern. Repeat/verify/recheck? Yes, of course, just as we do for minor abnormalities all the time. Again, this is not a reason for concern.
posted by docpops at 9:35 PM on May 15, 2009

119 isn't interesting. If I were your doc, I'd recheck once, then maybe on 6 & 12 months, and not do anything else unless it went below 100. The most likely cause is ITP. Treatment isn't needed unless the plt count is under 50 or so.
posted by neuron at 10:31 PM on May 15, 2009

I had a physical and CBC one summer when I was in college. I got exactly the same line you did, low platelets, come back in three months. I did, they did another blood draw, this one came back fine, I went on my merry way and yet to have any type of diagnosis, life-changing or otherwise. Sometimes things are off randomly and you're just fine. I would not prepare yourself for anything more dramatic than another blood stick in three months.
posted by fuzzbean at 10:37 PM on May 15, 2009

IANAD(yet), but I can tell you to definitely not freak out. There are so many things that can give you a low platelet count, and that's not even counting the possibility that you just have a lower count than average.

Take me -- I gave blood the other month and when they did a CBC on the spot, my platelets came back as 40. They stopped and told me to see a doctor. I did, and my platelet count was fine -- above 150 and within 1% of what it always is. Turns out there was something wrong with the machine at the blood bank.

Some people also have an issue where once their blood gets into a tube with EDTA (it's there to prevent clotting), the platelets clump together and give a falsely low reading.

Recheck it, yes, but really, don't worry!
posted by greatgefilte at 10:53 PM on May 15, 2009

In all likelihood everything is fine. That means that there are a ton of reasons why you would get such a result from one test on a certain day.

But keep in mind there will be a bias here: those who got a result and are too sick to read AskMe and/or have died, they're not exactly writing up here.

As a counter for those posters above, my uncle had a low platelet count and was dead 6 months later of leukemia. He was a bit older than you but in amazing shape. YMMV.

Nobody here knows what's wrong (or right) with you until the doctor re-tests and possibly rules out a few options.
posted by barnone at 11:46 PM on May 15, 2009

As another non-freak-you-out data point, I had a CBC done a couple years ago that showed my platelets around your number. It was retested a couple months later with the same result. I wasn't having any problems and the doctor wasn't concerned so we left it at that. I'm in my 20s.
posted by Durin's Bane at 5:34 AM on May 16, 2009

Some people also have an issue where once their blood gets into a tube with EDTA (it's there to prevent clotting), the platelets clump together and give a falsely low reading.

This is a somewhat accurate description of a fairly common phenomenon; it is not so much "some people" have this issue as it can be a problem if the blood was drawn slowly or was not mixed with the anticoagulant in the collection tube quickly or thoroughly enough. If the platelet count is critically important (as in a pt. going to surgery) the physician can ask for a manual platelet count which can correct for this phenomenon. (Typically the count is done automatically with some variant of a Coulter counter.) As mentioned above 150 (thousand per ml) is the lower limit of normal in most labs, so you are not that far out of the normal range. 50 is often used as the number we want a patient at before surgery, so that should give you an idea of where you fit in the range of normal to seriously abnormal.

I mention "normal in most labs" because due to variations in technique and equipment and patient populations, what is considered "normal" for a specific lab may vary a little from published normal values. Also important in interpreting lab results is knowing how normal results are defined. Basically, when setting up a lab they will recruit healthy volunteers to submit specimens; as a medical student I was paid $100 to give bone marrow to establish normal values for a new flow cytometer. After analysing a number of these "normal" samples, a range of values around the average are taken as the reference range. Typically this includes values within two standard deviations of the mean, or in other words 95% of the population. The flip side of this is that by defining normal in this way, 5% of healthy people will have an abnormal result on any given test. Whether or not you fall into this group is up to you and your physician to determine, based on your history, physical exam, and results of other tests. Rechecking it in a few months is a reasonable course of action if there are no reasons to think you have some sort of platelet disorder.
posted by TedW at 6:50 AM on May 16, 2009

TedW is alluding to the dirty little secret of clinical laboratory testing, in that we calculate the 'normal' range by the central 95% of normal, healthy adults who were selected to participate in providing a reference range for that lab test (ASSUMING a gaussian distribution, which of course, most tests are not). So even in the group of normals to start out with, 5% of the people tested had abnormal results by the just-calcuated reference range. What this boils down to is that every time you go to have 'some labs' run (and provided that you are 100% totally healthy) you compound that 5% risk of having an 'abnormal result' for every single test. So if you go have a CBC, BMP and your cholesterol checked, you're probably having ~12 different lab tests performed all with the same 5% chance of having an 'abnormal result'.

0.05 x 12 = 0.6, so you have a 60% chance of having an 'abnormal result' if you have 12 lab tests performed. Which highlights the true value of laboratory testing, which is the trends and changes of your results over time and not one spot-check at any given time.

What is even more sad is that many clinicians (and let alone a layperson) has no idea what we do in the lab or how these reference ranges are generated. So they treat these numbers as gospel, and that can lead to all sorts of problems.
posted by i_am_a_Jedi at 7:44 AM on May 16, 2009

Mrs Greycap has a blood disorder (ITP as mentioned above) which means that she often has a low platelet count. When she was diagnosed her platelet count was 7 and she had no symptoms/problems at all. Generally her count hovers around the 80 mark.

Anyway, the doctors don't seem to worry unless it drops below 20 and/or she has problems with bleeding. Even then her platelet count usually climbs back up on its own with no treatment. It really doesn't affect her life at all apart from the occasional medical appointments.

Which is all a roundabout way of saying that a count of 119, while below normal (150-400), doesn't sound like anything to freak out about. It seems like people can get by on many fewer platelets than average. Plus, as others have said, you may well find that its an anomaly and your count will be back up by your next blood test.
posted by greycap at 8:42 AM on May 16, 2009

The most likely cause is ITP

I had this. My platelet count was 7.

They did a bone marrow biopsy; I didn't have leukemia, I took prednisone for a while and now I am fine. I am not a doctor, but 119 isn't something I would even begin to ever freak out about.
posted by cosmic osmo at 7:40 PM on May 16, 2009

I have ITP also. It was diagnosed 8 years ago when I was pregnant for the first time. My hematologist says "most people have way more platelets than they need." I've only ever been treated for my ITP during pregnancy, and then it was with steroids to get my platelets up to 50k for labor and delivery. I did have a transfusion of platelets during surgery last winter.

You have to get really low to have any risk of spontaneous bleeding. I do bruise easily, sometimes. 119 is totally nothing to worry about.
posted by not that girl at 7:43 PM on May 16, 2009

Just to reassure the poster: There is no reason to believe you have ITP or any other problem based on what you posted here. If your physician (who knows more about you than all of us on AskMe combined) was concerned about ITP, leukemia, or some other problem he would be following up with other tests; if you are concerned call him and ask why he feels this is nothing to worry about. According to the National Heart Lung and Blood Institute, ITP affects 50-150 people per million each year, mostly children. Even though it is fairly common as blood disorders go you are unlikely to have it. Also, it is a diagnosis of exclusion, meaning that other causes of thrombcytopenia need to be ruled out before you can be said to have ITP; without other test results you cannot be said to have ITP. That is not to say there is nothing wrong with you, but based on what you said in the original post this isolated borderline abnormal test result seems unlikely to be anything to worry about.
posted by TedW at 3:39 AM on May 17, 2009

you compound that 5% risk of having an 'abnormal result' for every single test. So ... having ~12 different lab tests performed all with the same 5% chance of having an 'abnormal result'. 0.05 x 12 = 0.6, so you have a 60% chance of having an 'abnormal result' if you have 12 lab tests performed

Nice comment, but I believe the statistics work out to (1-0.05)^12 = 0.54, or 54%. Doing the math the way you have it makes a false positive an absolute certainty if you have 20 tests. Nonetheless, you make a very good point.
posted by exogenous at 9:57 AM on May 28, 2009

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