Reticulocyte Production Index (RPI)
Corrects reticulocyte count for degree of anaemia and reticulocyte maturation time. Differentiates hyperproliferative from hypoproliferative anaemia.
Score interpretation
RPI >= 2. Bone marrow responding appropriately. Suggests haemolysis, haemorrhage, or recovery from nutritional anaemia.
→ Investigate for haemolysis (LDH, haptoglobin, blood film) or active bleeding. If recovering: ensure adequate haematinic replacement.
RPI < 2. Inadequate marrow response. Suggests nutritional deficiency, marrow failure, chronic disease, or endocrine cause.
→ Check iron studies, B12, folate, renal function (EPO production), haematinics. Consider bone marrow biopsy if pancytopenia or unexplained.
Interpretation bands for the RPI. Apply clinical judgement and local guidance.
References
- Hillman RS, Finch CA. Red Cell Manual. 7th ed. Philadelphia: FA Davis; 1996.
- Bain BJ. Blood Cells: A Practical Guide. 5th ed. Wiley Blackwell; 2015.
Related
Curated clinical cross-links plus same-class fallbacks.
- Alendronic Acid (Alendronate) · Bisphosphonate (bone resorption inhibitor)
- Hydroxocobalamin · Vitamin B12 — Megaloblastic Anaemia
- Ferric Carboxymaltose (IV Iron — Pregnancy) · IV Iron Preparation — Iron Deficiency Anaemia in Pregnancy
- Teriparatide · Parathyroid Hormone Analogue (Anabolic Bone Agent)
- Denosumab · Anti-RANKL Monoclonal Antibody
- Vancomycin (Orthopaedic Bone and Joint Infections) · Glycopeptide Antibiotic
- Major Haemorrhage / Massive Transfusion · BCSH; RCOA; RCEM; RCS — BCSH Guidelines
- Anaemia Investigation · BSH / NICE
- Splenomegaly Workup · BSH; BMJ Best Practice
- Deep Vein Thrombosis Diagnosis and Treatment · NICE CG144 / NICE NG158
- Sickle Cell Crisis · BSH 2021 / BCSH
- Neutropenic Sepsis · NICE CG151 2012 / ESMO
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.
