OpiCalc

989 Clinical Tools

4Ts Score (HIT)aaIPI (Age-adjusted IPI)ABC Score (Massive Transfusion)Absolute Neutrophil Count Age-adjusted D-dimer Threshold aGvHD Grading (Glucksberg/MAGIC)AL Amyloidosis Staging (Mayo)Anti-Xa Monitoring Interpreter Antiphospholipid Syndrome Classification Binet / Rai Staging (CML)Blood Volume Calculator Caprini VTE Risk Score CISNE Score CLL-IPI Coombs-Negative Haemolysis Checklist Corrected Reticulocyte Count CRS Grading (ASTCT 2019)DAT Interpretation Algorithm Deauville Score Interpreter DIC Score (ISTH)DIPSS (MF)DIPSS-Plus (MF)DOAC Dose Selector DOAC Renal Dose Adjustment DRI (Disease Risk Index)Durie-Salmon Staging (historical)EBMT Risk Score ELN 2022 AML Risk Classification ELTS Score (CML)England & Fraser Index EUTOS Score (CML)Expected Hb Rise per RBC Unit Factor Inhibitor Bethesda Titre Interpreter Febrile Neutropaenia Risk (MASCC)Fibrinogen Replacement FLIPI (Follicular Lymphoma IPI)FLIPI-2 French TTP Score GAPSS (Global APS Score)Haemophilia Severity Classification HbS Percentage Target Calculator HCT-CI (Comorbidity Index)HEP Score Heparin Nomogram (Weight-based)Hepatic Iron Index HERDOO2 Rule HFE Haemochromatosis Risk Estimator ICANS Grading (ASTCT 2019)IMWG Response Criteria (Myeloma)IPI (International Prognostic Index)IPSID / Lugano Classification IPSS-M (Molecular IPSS)IPSS-R (Revised IPSS for MDS)Iron Deficit Calculator (Ganzoni Formula)ISS (Myeloma)ISTH Bleeding Assessment Tool (BAT)ISTH Non-Overt DIC Score ITP Bleeding Score iwCLL Response Criteria (2018)IWG ITP Response Criteria JAK2V617F Allele Burden Interpreter Karnofsky Performance Scale Leucostasis Risk Threshold Lupus Anticoagulant (LAC) Reporting Framework MAGIC aGvHD Biomarker Score MCV-based Anaemia Algorithm Mentzer Index MIPI (MCL IPI)MIPSS70+ v2.0 (MF)Mixing Study Interpretation MRD Assessment Threshold Interpreter mSMART 3.0 (Myeloma)MTP Activation Criteria NCCN-IPI NIH Chronic GvHD Scoring NTDT Iron Burden Estimator Padua RAM PBT (Paediatric BAT)PCNSL MSKCC Score PERC Rule Perioperative Anticoagulation Bridging PESI Score (PE Mortality)PLASMIC Score Platelet Increment Calculator (CCI)PNH Clone Size Interpreter R-IPI (Revised IPI)R-ISS (Revised ISS)Reticulocyte Index (RPI)Revised Geneva Score (PE)Revised Response Criteria (NHL)Revised Zubrod / ECOG Performance Shine & Lal Index Sickle Cell Disease Risk (TCD)SLiM-CRAB Criteria SOKAL Score (CML)Sokal/EUTOS/ELTS Comparison sPESI (Simplified PESI)TACO Risk Score Thalassaemia Transfusion Threshold Thrombocytopaenia Differential Thrombophilia Screening Eligibility Algorithm Time in Therapeutic Range (TTR)TLS Risk Classification Transferrin Saturation Calculator Vienna Prediction Model von Willebrand Factor Activity Interpreter Warfarin Dose Calculator Wells Score (DVT)Wells Score (PE)WHO 2022 AML Classification Mapper WHO Bleeding Scale YEARS Algorithm

Haemophilia Severity Classification

Activity Thresholds: WFH definitions based on baseline factor (VIII/IX) activity. While lab results define the class, the clinical phenotype determines treatment strategy.

Factor Activity (%)

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Classifying the severity of newly diagnosed Haemophilia A (Factor VIII deficiency) or Haemophilia B (Factor IX deficiency).

Correlating laboratory factor activity with clinical bleeding phenotype.

Guiding the necessity for primary prophylaxis vs. episodic (on-demand) treatment.

Patient Population

Adults and children with a baseline deficiency of factor VIII or IX.

Section 2

Formula & Logic

Activity Thresholds

Severity	Factor Level (% or IU/mL)	Clinical Phenotype
Severe	< 1% (< 0.01)	Frequent spontaneous bleeds into joints or muscles; often diagnosed in infancy.
Moderate	1 - 5% (0.01 - 0.05)	Few spontaneous bleeds; prolonged bleeding with minor trauma or surgery.
Mild	6 - 40% (0.06 - 0.40)	No spontaneous bleeding; hemorrhage only with significant trauma or major surgery.

Section 3

Pearls/Pitfalls

The 'Invisible' Severe

While laboratory thresholds are standard, some patients with < 1% activity have a "moderate" clinical phenotype, while others with 2-3% activity bleed spontaneously like "severe" patients. Clinical phenotype should ultimately guide prophylaxis decisions.

Emicizumab Impact

In patients with severe Haemophilia A, Emicizumab prophylaxis can transition the bleeding clinical phenotype from "Severe" to effectively "Mild," allowing for much greater physical activity.

Section 4

Evidence Appraisal

Primary Strategy

WFH Guidelines for the Management of Hemophilia, 3rd edition.

Srivastava A et al. • Haemophilia. 2020;Global consensus on severity thresholds.

View Source

Definitions in hemophilia: on behalf of the scientific and standardization committee of the international society on thrombosis and haemostasis.

White GC et al. • Thrombosis and Haemostasis. 2001;85(3):560.

View Source

Section 5

Literature

Validation

These thresholds have been the foundation of haemophilia care since the 1950s, refined by the ISTH in 2001 to ensure uniform language in global clinical trials.

Last Comprehensive Review: 2026

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Classifying the severity of newly diagnosed Haemophilia A (Factor VIII deficiency) or Haemophilia B (Factor IX deficiency).

Correlating laboratory factor activity with clinical bleeding phenotype.

Guiding the necessity for primary prophylaxis vs. episodic (on-demand) treatment.

Patient Population

Adults and children with a baseline deficiency of factor VIII or IX.

Section 2

Formula & Logic

Activity Thresholds

Severity	Factor Level (% or IU/mL)	Clinical Phenotype
Severe	< 1% (< 0.01)	Frequent spontaneous bleeds into joints or muscles; often diagnosed in infancy.
Moderate	1 - 5% (0.01 - 0.05)	Few spontaneous bleeds; prolonged bleeding with minor trauma or surgery.
Mild	6 - 40% (0.06 - 0.40)	No spontaneous bleeding; hemorrhage only with significant trauma or major surgery.

Section 3

Pearls/Pitfalls

The 'Invisible' Severe

Emicizumab Impact

In patients with severe Haemophilia A, Emicizumab prophylaxis can transition the bleeding clinical phenotype from "Severe" to effectively "Mild," allowing for much greater physical activity.

Section 4

Evidence Appraisal

Primary Strategy

WFH Guidelines for the Management of Hemophilia, 3rd edition.

Srivastava A et al. • Haemophilia. 2020;Global consensus on severity thresholds.

View Source

Definitions in hemophilia: on behalf of the scientific and standardization committee of the international society on thrombosis and haemostasis.

White GC et al. • Thrombosis and Haemostasis. 2001;85(3):560.

View Source

Section 5

Literature

Validation

These thresholds have been the foundation of haemophilia care since the 1950s, refined by the ISTH in 2001 to ensure uniform language in global clinical trials.

Last Comprehensive Review: 2026

Related Hematology Tools

Shine & Lal Index

Corrected Reticulocyte Count

Transferrin Saturation Calculator

Iron Deficit Calculator

HFE Haemochromatosis Risk Estimator

Hepatic Iron Index

DAT Interpretation Algorithm

Coombs-Negative Haemolysis Checklist

PLASMIC Score

French TTP Score

Have feedback about this calculator?Let us know.

Haemophilia Severity Classification

Activity Thresholds: WFH definitions based on baseline factor (VIII/IX) activity. While lab results define the class, the clinical phenotype determines treatment strategy.

Factor Activity (%)

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Classifying the severity of newly diagnosed Haemophilia A (Factor VIII deficiency) or Haemophilia B (Factor IX deficiency).

Correlating laboratory factor activity with clinical bleeding phenotype.

Guiding the necessity for primary prophylaxis vs. episodic (on-demand) treatment.

Patient Population

Adults and children with a baseline deficiency of factor VIII or IX.

Section 2

Formula & Logic

Activity Thresholds

Severity	Factor Level (% or IU/mL)	Clinical Phenotype
Severe	< 1% (< 0.01)	Frequent spontaneous bleeds into joints or muscles; often diagnosed in infancy.
Moderate	1 - 5% (0.01 - 0.05)	Few spontaneous bleeds; prolonged bleeding with minor trauma or surgery.
Mild	6 - 40% (0.06 - 0.40)	No spontaneous bleeding; hemorrhage only with significant trauma or major surgery.

Section 3

Pearls/Pitfalls

The 'Invisible' Severe

Emicizumab Impact

In patients with severe Haemophilia A, Emicizumab prophylaxis can transition the bleeding clinical phenotype from "Severe" to effectively "Mild," allowing for much greater physical activity.

Section 4

Evidence Appraisal

Primary Strategy

WFH Guidelines for the Management of Hemophilia, 3rd edition.

Srivastava A et al. • Haemophilia. 2020;Global consensus on severity thresholds.

View Source

Definitions in hemophilia: on behalf of the scientific and standardization committee of the international society on thrombosis and haemostasis.

White GC et al. • Thrombosis and Haemostasis. 2001;85(3):560.

View Source

Section 5

Literature

Validation

These thresholds have been the foundation of haemophilia care since the 1950s, refined by the ISTH in 2001 to ensure uniform language in global clinical trials.

Last Comprehensive Review: 2026

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Classifying the severity of newly diagnosed Haemophilia A (Factor VIII deficiency) or Haemophilia B (Factor IX deficiency).

Correlating laboratory factor activity with clinical bleeding phenotype.

Guiding the necessity for primary prophylaxis vs. episodic (on-demand) treatment.

Patient Population

Adults and children with a baseline deficiency of factor VIII or IX.

Section 2

Formula & Logic

Activity Thresholds

Severity	Factor Level (% or IU/mL)	Clinical Phenotype
Severe	< 1% (< 0.01)	Frequent spontaneous bleeds into joints or muscles; often diagnosed in infancy.
Moderate	1 - 5% (0.01 - 0.05)	Few spontaneous bleeds; prolonged bleeding with minor trauma or surgery.
Mild	6 - 40% (0.06 - 0.40)	No spontaneous bleeding; hemorrhage only with significant trauma or major surgery.

Section 3

Pearls/Pitfalls

The 'Invisible' Severe

Emicizumab Impact

In patients with severe Haemophilia A, Emicizumab prophylaxis can transition the bleeding clinical phenotype from "Severe" to effectively "Mild," allowing for much greater physical activity.

Section 4

Evidence Appraisal

Primary Strategy

WFH Guidelines for the Management of Hemophilia, 3rd edition.

Srivastava A et al. • Haemophilia. 2020;Global consensus on severity thresholds.

View Source

Definitions in hemophilia: on behalf of the scientific and standardization committee of the international society on thrombosis and haemostasis.

White GC et al. • Thrombosis and Haemostasis. 2001;85(3):560.

View Source

Section 5

Literature

Validation

These thresholds have been the foundation of haemophilia care since the 1950s, refined by the ISTH in 2001 to ensure uniform language in global clinical trials.

Last Comprehensive Review: 2026

Related Hematology Tools

Shine & Lal Index

Corrected Reticulocyte Count

Transferrin Saturation Calculator

Iron Deficit Calculator

HFE Haemochromatosis Risk Estimator

Hepatic Iron Index

DAT Interpretation Algorithm

Coombs-Negative Haemolysis Checklist

PLASMIC Score

French TTP Score

Have feedback about this calculator?Let us know.