Transfusion medicine

The researches find that the thrombocytopenia and bleeding are events that often occur together in neonates, this may not signify cause and effect. In fact, one study reported that 91% of neonates with low platelet counts did not develop major hemorrhage. Despite this, platelet counts are regarded as a reliable marker to determine the need for platelet transfusion. In this case study, scientists used flow cytometry as a means of determining platelet function in neonates.Most of the current methods used to determine platelet function require large volumes of blood; which is difficult to collect from premature infants.

The need for platelet transfusion

Flow cytometry can be a potent method to counter this disadvantage as it requires smaller volumes of blood; such as <500 μL. In this case study; neonates from three age groups were chosen: <29 weeks, 29–36 weeks, and >36 weeks old, and 5000 platelets were measured using FACS. One of the assays used measured how a blood sample responds to fibrinogen. Fibrinogen is a protein that promotes blood clotting by activating and binding to platelets.

To determine fibrinogen levels; 5uL of blood is incubate with various concentrations of adenosine diphosphate and its affinity for fibrinogen is test using a fluorescently label anti-fibrinogen antibody. It is find that the baseline binding to fibrinogen was below 10% for all neonates; however; the percentage of platelets that bind to fibrinogen increase when increasing levels of ADP or C-reaction proteins (proteins that are produce during inflammation or infection) are add.

Labeled anti-fibrinogen antibody

The study found a high incidence of thrombocytopenia among neonates; especially when accompanied by co-morbidities, such as sepsis. As P-selectin is a protein whose levels reflect activation of platelets; its levels were measure in this study. It is find that premature babies had less P-selectin on their surface; compare to babies born between 30–36 weeks or term babies. Also, neonates with a suspected case of sepsis or infection showed reduced activation of platelets. But This suggests that sepsis can be a potential risk factor for hemorrhage in newborns.

In many cases, there is often a delay between collecting the sample; conducting the assay, and finally analyzing it in the flow cytometer in a busy clinic. To determine if these lag periods could alter the results; samples from three healthy; individuals are take and artificial time delays are set between ;the various stages of the experiment. These included: venepuncture, stimulating the platelets, and performing flow cytometry. The baseline activation and platelet response are not alter, showing that time delays do not cause any changes to the results.