The Use of Immature Platelet Fraction (IPF) as a Non-Invasive Marker for Assessing Bone Marrow Activity in Dogs and Cats: A Scoping Review Abstract

Background: Evaluating bone marrow is an invasive and expensive procedure that frequently necessitates sedation or anesthesia in dogs and cats. The immature platelet fraction (IPF), along with associated reticulated platelet parameters, has been suggested as a non-invasive alternative for assessing megakaryocytic activity. However, a comprehensive assessment of the depth and balance of evidence across the two most prevalent companion animal species has not been conducted previously. Objective: This scoping review aims to provide a map and chart of the current veterinary literature on IPF and reticulated platelets as indicators of bone marrow activity in dogs and cats, and to determine whether there is sufficient evidence for a systematic review with meta-analysis or only a scoping-level synthesis. Methods: Following the Population-Concept-Context (PCC) framework and the PRISMA Extension for Scoping Reviews (PRISMA-ScR guidelines, an exhaustive search was conducted in PubMed/MEDLINE, Embase, Web of Science, Scopus and CAB Abstracts. The parameters of immature and reticulated platelets have been examined in relation to bone marrow and platelet status. IPF and reticulated platelets were focused on in relation to the condition of the bone marrow and platelets. Records were reviewed to ensure eligibility, and a standard data sheet was used to extract data. Results: Of 35 records identified, 10 met the eligibility criteria. Nine of the ten included studies reported data only in dogs; a single retrospective study reported data in both dogs and cats, and no study addressed cats exclusively. Only one study used a direct bone-marrow reference standard (megakaryocyte cytology); the remainder relied on indirect or clinical classification. Conclusions: Evidence for IPF/reticulated platelets as a bone-marrow marker is considerably more developed in dogs than in cats. Feline data are essentially limited to a single retrospective analyzer study. Given the small number of studies and marked methodological heterogeneity, a full systematic review with meta-analysis is not currently feasible; a scoping review is the appropriate and informative synthesis at this stage.