Transplacental transmission of EDTA dependent pseudothrombocytopenia in a neonate

doi:10.4236/ojped.2011.13011

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Open Journal of Pediatrics, 2011, 1, 39-40 OJPed

doi:10.4236/ojped.2011.13011 Published Online September 2011 (http://www.SciRP.org/journal/ojped/).

Published Online September 2011 in SciRes. http://www.scirp.org/journal/OJPed

Transplacental transmission of EDTA dependent

pseudothrombocytopenia in a neonate

Ali Bay1*, Ercan Sivasli1, Safak Taviloglu1, Goksel Leblebisatan2, Enes Coskun1, Unal Uluca1

1Department of Pediatric s , Gaziantep University, Gaziant ep, Turkey;

2Gaziantep Children Hospital, Gaziantep, Turkey.

Email: *[email protected]

Received 22 April 2011; revised 2 June 2011; accepted 25 July 2011.

ABSTRACT

Verifying platelet counts can prevent unwarranted

diagnostic tests and transfusions. In case of throm-

bocytopenia, if the clinical picture and history do not

suggest bleeding tendency, one should always per-

form peripheral blood smear by directly obtaining

blood by finger puncture before doing any further

tests. If the peripheral blood smear exhibits platelet

clumps, pseudothrombocytopenia should always be

remembered. In this case, we present a neonate with

a diagnosis of transplacental transmission of EDTA-

dependant pseudothrombocytopenia.

Keywords: Thrombocytopenia; Pseudothrombocytopenia;

Neonate

1. INTRODUCTION

Pseudothrombocytopenia or spurious thrombocytopenia

is an in vitro laboratory finding usually associated with

the use of ethylenediamine tetraacetic acid (EDTA) in

blood collection tubes [1]. It is due to platelet clumping

when blood is anticoagulated with EDTA. EDTA while

binding calcium ions releases glycoprotein IIb (GpIIb)

epytope by interacting with the glycoprotein IIb-IIIa

(GpIIb-IIIa) molecule on the platelet membrane [2,3]. If

the patient has autoantibodies (usually IgG type immu-

noglobulins) against these epytopes, they cause clump-

ing of these platelets by binding to the epytopes on their

surfaces. These thrombocyte clumps are considered as

leukocyte by the automated blood counters due to their

volumes and so the platelet counts are estimated as low.

We describe a case of transient congenital pseudoth-

rombocytopenia in a baby born to a mother with pseu-

dothrombocytopenia.

2. CASE REPORT

A 28 year old woman was found to have persistent

thrombocytopenia by routine electronic blood counting.

There was no history of bleeding tendency though her

first childbirth was via C/S. In her second pregnancy, the

automatic platelet count on EDTA-anticoagulated sam-

ple was 33.000/mm³; her peripheral blood smear exhib-

ited multiple platelet clumps. Her blood was collected in

heparin anticoagulated tube and her platelet count was

184.000/mm³. She was diagnosed as EDTA dependant

pseudothrombocytopenia. She delivered her baby via

C/S without complications.

The laboratory analyses of newborn show that throm-

bocytopenia with a level of platelet count 56.000/mm³.

She had no bleeding tendency. In her blood smear, sev-

eral large platelet clumps were detected. We considered

that this low platelet count might be due to EDTA-in-

duced aggregation of the platelets. Therefore, we meas-

ured platelet count of his blood samples obtained by

venipuncture in different test tubes, each containing so-

dium citrate or standard heparin. Platelet counts of blood

samples in test tubes containing sodium citrate or hepa-

rin were found to be 154.000/mm3 and 161.000/mm3,

respectively. So the baby was considered to have pseudo

thrombocytopenia and discharged from the hospital.

Finally, du ring her last follow up visit, she was 6 month s

old and the baby’s platelet count was normal, even in the

presence of EDTA. Repeat counts performed over the

following months showed persistence of pseudothrom-

bocytopenia in th e mother.

3. DISCUSSION

The prevalence rate of EDTA-dependent pseudothrom-

bocytopenia was reported as 0.07% to 0.20% in the lit-

erature. [4]. It is almost always discovered during rou-

tine hematologic tests. Pseudothrombocytopenia is seen

in patients whose blood is taken into EDTA containing

tubes. The incidence of autoantibodies causing clumping

of platelets due to the presence of EDTA is 1/1000 in

humans [5]. These autoantibodies are either present life-

long time or may be temporary secondary to the pres-

ence of infections or use of drugs. These autoantibodies

A. Bay et al. / Open Journal of Pediatrics, 2011, 1, 39-40

can cross the placenta and cause thrombocytopenia in

neonate [5]. This case documents transplacental trans-

mission of the plasmatic factor probably an IgG, respon-

sible for pseudthrombocytopenia. If there is thrombocy-

topenia, a peripheral blood smear with blood counts,

taken into tubes containing citrate or heparin as antico-

agulant should be performed.

In case of low thrombocyte level which ob tained with

an electronic counter peripheral smear should be prepar-

ed from both patient’s fingertip and blood sample with

EDTA. Also platelet count should be repeated with an-

other anticoagulant like citrate or heparin instead of

EDTA. Repeated thrombocyte counts with other antico-

agulants are usually found normal in range. Thrombo-

cytes sometimes surround in leucocytes (thrombocyte

satellism) which form a cluster. These clusters can not be

counted correctly by electronic blood counter instru-

ments. So this should be ruled out when thrombocyto-

penia is detected. It should be kept in mind that low

thrombocyte counts can be obtained due to aggregation

of thrombocyte when blood samples are taken improp-

erly (insufficient mix of anticoagulant and blood sample,

difficulty in venous access). When low platelet counts

are found from the blood samples of patients whom have

been difficulties in venous access, peripheral blood

smear should be done and examined under microscope.

MPV (mean platelet volume) is also measured in full

blood count instruments beside thrombocyte count. In

patients with low platelet levels; if MPV value is high

the differential diagnosis should include acute ITP, Ber-

nard-Soulier syndrome and also one should always re-

member the possibility of formation of thrombocyte

clusters and further investigation should be performed

according to these causes .

One has to decide if thrombocytopenia is real or

pseudo before making further diagnostic tests, a periph-

eral smear should always be done with complete blood

counts.

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