ITP Support Association



The Curious Case of the Clumping Platelets

The first time I heard the phrase CLUMPING PLATELETS was on January 26th this year when following my routine (as if anything can ever be routine in ITP) 3 month blood test on January 15th. I got a telephone call from my specialist advising that I would have to get another blood test as the one taken was inconclusive. They could not get a definite platelet count because my platelets had clumped.

So what exactly is PLATELET CLUMPING and why does it occur ? Well thanks to Shirley at the ITP Support Association and her getting me an explanation from Professor George my mind was put at ease and my natural curiosity satisfied.

The way I understand it is that when a blood test is done a chemical is routinely used in the test tube on the blood sample. The chemical used in most cases is EDTA (Ethylenediaminetetraacetic acid (say that quickly after a few glasses of wine ). Sometimes, as happened in my case this January platelets clump in the test tube when EDTA is used.

The blood sample can be tested using a different chemical to get a platelet count if EDTA produces CLUMPING PLATELETS. So when I subsequently had yet another blood test on February 24th I had 3 samples taken, one to be tested with EDTA, the second to be tested in CITRATE (an alternative chemical) and thirdly another to be tested using Lithium Heparin (yet another chemical). The results came back satisfactory this time with a platelet count of 139 and amazingly they did NOT CLUMP this time in the EDTA.

So yet another curious episode in what after all is a curious condition called ITP.

Has CLUMPING PLATELETS happened to anyone else ? If so please do tell us ......I look forward to your thoughts/comments fellow ITP voyagers !!!!!

3 Replies

Yes this happened to me on a number of occasions as well when my platelets were very low so I had to be retested in Citrate.


I had clumping platelets just before an operation about 8 years ago but they said they thought the count was high enough not to retest so the op went ahead. :-)


Hello it happens to me many times.. it was always frustrating when they take my blood samples at the medical clinic.. today i took two samples. One with the machine i think they used edtaand i got 65, but when they tried to manual it using micriscope (blood smear) i got 244..


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