This document discusses various platelet indices used in interpreting platelet histograms and their clinical significance. It defines plateletcrit (PCT) as the volume of platelets expressed as a percentage of total blood volume, with a normal range of 0.22-0.24%. It describes platelet distribution width (PDW) as measuring the variation in platelet size, with a normal range of 25-65, and higher values associated with vascular disease or cancer. It also defines platelet large cell ratio (P-LCR) as measuring larger platelets between 12-30 femtoliters, with increased levels seen in hyperlipidemia and autoimmune thrombocytopenic purpura. Mean platelet volume (MPV) is defined as the average

1. Platelet Indices
Dr. Umme Habiba

2. Histogram for Blood Cell Counts

4. Interpretation of normal platelet histogram: Normal platelet histogram is left
skewed (arrow, A), MPV calculation (B), PDW calculation (C), thrombocytosis vs
normal curve (D), thrombocytopenia vs normal curve (E), PL flag (F) and PU flag
(G).

6. Plateletcrit PCT
◦ Volume of platelets expressed as a % of total blood volume.
◦ Formula: PCT = platelet count × MPV / 10,000
◦ Optimal Result: 0.22 - 0.24 %.
◦ Low Plateletcrit indicates true thrombocytopenia.

7. PDW

8. PDW
◦ PDW means Platelet Distribution Width i.e. how widely are
platelets dispersed depending upon variation in their size.
◦ It ranges from ( 25-65).
◦ A high PDW means there is a great variation in size, which may be
associated with vascular (blood vessel) disease or certain cancers.

9. Platelet Large Cell Ratio

10. P-LCR:
• P-LCR means Platelet large cell ratio and it’s calculated in
automated blood analyzers using this formula:
• P-LCR = P-LCC/PLT.
• PLT = Total Platelets Count.
• P-LCC = platelets larger than 12 fl and smaller than 30fl.

11. • The platelet–large cell ratio (P-LCR) is an indicator of circulating
larger platelets (>12 fl) and the best tool to assess megakaryocyte
activity
• Increased percentage of large platelets (P-LCR) is observed in
patients with Hyperlipidaemia and suggest possible risk of
thrombosis.
• An increase in P-LCR + MPV + PDW has been observed in
autoimmune thrombocytopenic purpura.

12. MPV
◦ MPV means the average volume of counted platelets.
◦ It is analogous to the erythrocyte MCV.
◦ MPV (fL) = PCT% / PLT count
◦ Reference range= 8-12 fL

13. Clinical Significance
High MPV
◦ Thrombocytopenia.
◦ Myeloproliferative disorders
◦ Preeclampsia
◦ Heart disease
◦ Diabetes
◦ Hemolytic anemia
Low MPV
◦ Certain cancers
◦ Drug-induced
◦ Aplastic anemia
◦ Autoimmune diseases
◦ Bacterial or viral infections
◦ Genetic conditions
◦ Alcohol use disorder (AUD)

16. THANKS