The Sysmex XN-series haematology analyser has a fluorescent channel to measure immature platelet fraction (IPF). Specialised fluorescence flow cytometry within the PLT-F channel is used to generate an accurate and precise platelet count, referred to as the fluorescent platelet count (PLT-F), which is comparable to the CD41/CD61 reference method. This channel can give an accurate count even in platelet disorders, whether the disorder is due to platelet number or platelet size.
The PLT-F channel analyses a 5-fold larger sample volume of the aspirated sample compared to the Sheath Flow (DC) Detection measurement, which results in the high measurement accuracy in the low concentration range. The PLT-F channel also provides information about immature platelets in the form of the immature platelet fraction (IPF).
This parameter is expressed as a proportional value of the total platelet count (%-IPF), as well as absolute immature platelet (A-IPF), which is a derived value from the total platelet count and %-IPF.
Immature platelets are the newly released platelets from the bone marrow by megakaryocytes. They have a short lifespan (< 24 hours). The IPF is a helpful and non-invasive biomarker for the diagnosis of thrombocytopenia. It makes a distinction between bone marrow failures and peripheral platelet destruction because it is an indicator of megakariopoetic activity.
The IPF can be used to:
1. Indicate whether the cause of thrombocytopenia is due to destruction or production issues:
a. In platelet destruction, there would be a high IPF as the bone marrow is producing the platelets before they are destroyed (high bone marrow activity)
b. In production issues, as the bone marrow is not producing any platelets (bone marrow failure), then the IPF would be low.
2. Assess bone marrow recovery