Apheresis Clinical Calculators

Validated formulas for therapeutic plasma exchange, RBC exchange, leukocytapheresis, HPC collection, citrate management, and more — based on ASFA guidelines and peer-reviewed literature.

14 Calculator Modules ASFA 9th Edition Nadler's Formula Validated Clinical Formulas
🔒 HIPAA Notice: Do not enter real patient names, MRNs, or identifying information. Use de-identified values only.
Foundation Calculator

Patient Body Parameters Live

Calculates Total Blood Volume (TBV), Total Plasma Volume (TPV), and Red Cell Volume (RCV). Results carry forward automatically to all other calculators.

Nadler's Formula for Total Blood Volume (TBV)

Males: TBV (L) = (0.3669 × H³) + (0.03219 × W) + 0.6041 Females: TBV (L) = (0.3561 × H³) + (0.03308 × W) + 0.1833 Simplified: TBV (mL) = 70 mL/kg × Weight [Males] / 65 mL/kg [Females]

H = Height in meters · W = Weight in kg · Nadler's formula is the standard used by Spectra Optia® and Haemonetics® MCS+

📖 Nadler et al., Surgery 1962 · Lemmens et al., Obes Surg 2006
Pre-procedure value

📊 Patient Parameters

Total Blood Volume (Nadler)
mL
TBV (Simplified)
mL
Total Plasma Volume (TPV)
mL
Red Cell Volume (RCV)
mL
Clinical Use: TPV is used to prescribe TPE volume (typically 1.0–1.5× TPV per session). RCV is used to calculate donor RBC volume for erythrocytapheresis. These values are automatically used in other calculator modules.
ParameterAverage Adult MaleAverage Adult FemaleClinical Significance
TBV5,000–6,000 mL4,000–5,000 mLBasis for all apheresis volume calculations
TPV2,700–3,200 mL2,300–2,800 mLDetermines TPE prescription volume
RCV2,200–2,800 mL1,600–2,200 mLDetermines RBC exchange donor volume
Hematocrit40–52%36–48%Key variable; changes during procedure
Plasma Exchange Calculator

Therapeutic Plasma Exchange (TPE) Live

Calculates plasma volume to process, replacement fluid volumes, and estimated solute reduction per session. ASFA recommends 1.0–1.5× plasma volumes per session for most indications.

TPE Volume & Solute Removal

TPE Volume (mL) = Target Plasma Volumes × TPV Residual Fraction = e^(−TPE Volume / TPV) % Removed = (1 − Residual Fraction) × 100

Assumes single-compartment model, intravascular distribution, and isovolumetric exchange. Valid for IgG, IgM, fibrinogen, and other high-MW substances.

📖 ASFA 9th Edition (2023) · Cervantes et al., AJKD 2023 · Reverberi, Blood Transfus 2007
ℹ️

Auto-fill: If you calculated Patient Body Parameters first, the TPV field below is pre-filled. Otherwise, enter TPV manually.

mL — from Patient Parameters or enter manually

📊 TPE Prescription

Volume to Process (Per Session)
mL per session
Estimated % Removed (Per Session)
% of intravascular substance
Albumin Volume (5%)
mL per session
FFP Volume
mL per session
Replacement FluidStandard UsePreferred WhenAvoid When
5% AlbuminFirst-line for most indicationsRoutine TPE, maintenance sessionsActive bleeding, coagulopathy, TTP (use FFP)
Fresh Frozen Plasma (FFP)TTP (mandatory), anti-GBM, HUSCoagulopathy, factor replacement neededRoutine use (risk of allergic reactions, TRALI)
50% Albumin / 50% FFPCompromise approachMild coagulopathy, last few sessionsActive TTP (use 100% FFP)
Normal SalinePartial replacement onlyMild hyperviscosity, volume managementFull-volume replacement (hypoproteinemia risk)
Kinetics Calculator

Solute Removal Kinetics

Models the exponential removal of intravascular substances during TPE. Useful for understanding how many sessions are needed to achieve a target reduction level.

One-Compartment Removal Model

Residual Concentration (%) = 100 × e^(−v/V) Where: v = volume exchanged (mL) · V = plasma volume (mL)

Valid for high-molecular-weight substances (IgG, IgM, fibrinogen, LDL) that are predominantly intravascular.

📖 Reverberi & Reverberi, Blood Transfus 2007 · Wiener & Wexler 1946
mL
% of substance in plasma
Any unit (mg/dL, g/L, titer, etc.)

📊 Predicted Removal by Session

Session Volume Exchanged Residual (%) Estimated Level % Removed (Cumulative)
Red Cell Procedure Calculator

RBC Exchange — Procedure Setup Live

Calculates Fraction of Cells Remaining (FCR) and the Replaced: Exchange volume for automated RBC exchange. Enter patient data, select exchange type, set fluid and run targets — FCR auto-calculates from HbS% values.

RBC Exchange Core Formulas

TBV (Males, mL) = (0.3669 × H³ + 0.03219 × W + 0.6041) × 1000 TBV (Females, mL) = (0.3561 × H³ + 0.03308 × W + 0.1833) × 1000 FCR (%) = (Target HbS% / Starting HbS%) × 100 Replaced: Exchange (mL) = −ln(FCR) × TBV × √(Patient Hct × Target Hct) / Exchange Fluid Hct Predicted Post-HbS (%) = Starting HbS% × FCR

H = Height in meters · W = Weight in kg · Hct values as decimals · FCR = Fraction of Cells Remaining

📖 Nadler et al., Surgery 1962 · ASFA 9th Edition · Terumo BCT™ RBCX Protocol

Patient Data

Pre-procedure value
Added to total exchange volume

Fluid Data

Hct of donor pRBC unit(s) used

Run Targets

Quick Presets:

📊 RBC Exchange — Procedure Setup Results

FCR
%
Replaced: Exchange
mL
Patient TBV
mL
Predicted Post-HbS
%
Erythrocytapheresis Calculator

RBC Exchange (RBCX) — Sickle Cell Disease Live

Calculates Fraction of Cells Remaining (FCR) and donor pRBC volume needed to achieve a target post-procedure HbS%. Supports Exchange Only and Depletion/Exchange protocols.

Core Formulas — Automated RBC Exchange

FCR from HbS%: FCR = Target HbS (%) ÷ Starting HbS (%) RCV (mL) = TBV × (Pre-Hct ÷ 100) Exchange Only — Donor Volume: V_donor = TBV × [(Target Hct − Pre-Hct × FCR) ÷ Donor Hct] Units Needed: N = V_donor ÷ Unit Volume (mL)
📖 Nadler et al., Surgery 1962 · Fasano et al., Transfusion 2015 · ASFA 9th Ed. Cat I, Grade 1C
ℹ️

FCR ≠ HbS% — Key Distinction

FCR (Fraction of Cells Remaining) is the % of the patient's original RBC volume remaining after the procedure. HbS% is the % of sickled hemoglobin. FCR = HbS% only if the patient's starting HbS is 100%. For transfused patients, always calculate FCR from HbS% using the formula above.

Exchange Only: Direct replacement of patient RBCs with donor RBCs. Most common.  |  Depletion/Exchange: Depletes patient RBCs first, then exchanges. Requires fewer donor units. Recommended when pre-Hct ≥26%.

Screen A — Patient Data
Screen B — Procedure Targets
Acute crisis: <30% · Chronic: <50%
Typical: 30–36%
Screen C — Donor Unit Data
Typical leukoreduced pRBC: 55–70%
Standard pRBC unit: 250–350 mL
Quick Presets

🔴 RBC Exchange Results

FCR (Fraction of Cells Remaining)
% patient RBCs remaining
Donor pRBC Volume Needed
mL
Donor Units Needed
units
Patient TBV
mL (Nadler)
Patient RCV
mL
Predicted Post-HbS
%
HbS Reduction
% reduction
Spectra Optia® Entry Values
Protocol
FCR to Enter
Target Hct
Donor Hct
Cell Reduction Calculator

Leukocytapheresis — WBC Reduction

Estimates post-procedure WBC count and sessions needed to reach a target WBC level. Typically indicated for symptomatic hyperleukocytosis (WBC >100×10⁹/L).

WBC Reduction Estimate

Post-WBC = Pre-WBC × (1 − Reduction Rate) Sessions to Target = log(Target/Pre) / log(1 − Rate) WBCs Removed = Pre-WBC × Rate × TBV (L)
📖 ASFA 9th Edition · Stucki et al., J Clin Apher 2012
⚠️

Emergency Threshold: Leukapheresis is typically indicated when WBC >100×10⁹/L with symptomatic leukostasis. In AML, consider at WBC >50×10⁹/L with symptoms. This is a temporizing measure — cytoreductive chemotherapy must follow.

From Patient Parameters

📊 Leukocytapheresis Estimates

Estimated Post-WBC (1 Session)
×10⁹/L
WBC Reduction (1 Session)
% reduction
Sessions to Reach Target
sessions (estimated)
WBCs Removed (1 Session)
×10⁹ cells
Cellular Therapy Calculator

HPC Stem Cell Collection (Leukapheresis)

Predicts CD34+ cell yield from peripheral blood leukapheresis. Used to plan collection sessions and determine if target dose will be achieved.

CD34+ Yield Prediction

Predicted Yield = PB CD34+ (cells/µL) × 1000 × Blood Vol Processed (L) × CE₂ (%) Target Dose: ≥2×10⁶ CD34+/kg (minimum) · ≥4×10⁶ CD34+/kg (optimal)
📖 Sheppard et al., BBMT 2016 · Jacob et al., Transfusion 2021
Day-of-collection peripheral blood
Typically 3–5× TBV
Device-specific; typically 30–50%
For dose/kg calculation

📊 HPC Collection Prediction

Predicted CD34+ Yield
×10⁶ cells
Dose per kg (Recipient)
×10⁶ CD34+/kg
Target Achievement
vs. 4×10⁶/kg optimal
Sessions to Optimal Dose
sessions estimated
PB CD34+ CountMobilization StatusExpected YieldClinical Action
<5 cells/µLPoor mobilizationUnlikely to meet minimum doseConsider plerixafor rescue, delay collection
5–10 cells/µLMarginalMay require multiple sessionsProceed with caution; consider plerixafor
10–20 cells/µLAdequateLikely to meet minimum (2×10⁶/kg)Proceed with collection
>20 cells/µLGood mobilizationLikely to meet optimal (4×10⁶/kg)Proceed; single session may suffice
Plateletpheresis Calculator

Platelet Collection Efficiency (CE)

Calculates CE1 and CE2 for plateletpheresis and estimates the therapeutic dose. Used for donor qualification, device performance monitoring, and quality control.

Collection Efficiency Formulas

CE₁ (%) = (Collected Platelets) / (Pre-count × TBV) × 100 CE₂ (%) = (Collected Platelets) / (Pre-count × WB Volume Processed) × 100 Platelet Yield = Product Volume (mL) × Product PLT Count (×10⁹/mL) Therapeutic Dose: ≥3.0×10¹¹ platelets per unit (AABB standard)
📖 Jaime-Pérez et al., J Clin Apheresis 2017 · Castillo-Aleman et al., Transfusion & Apheresis Sci 2023
From Patient Parameters

📊 Plateletpheresis Results

Platelet Yield
×10¹¹ platelets
Collection Efficiency (CE₁)
% (vs. TBV)
Collection Efficiency (CE₂)
% (vs. WB processed)
Therapeutic Dose Met?
≥3.0×10¹¹ = AABB standard
Safety Calculator

Citrate Toxicity Risk Assessment Live

Calculates citrate infusion rate and assesses hypocalcemia risk based on blood flow rate, ACD-A ratio, and patient weight.

Citrate Infusion Rate

ACD-A Infusion Rate (mL/min) = Blood Flow Rate (mL/min) ÷ Inlet:AC Ratio Citrate Dose (mg/kg/min) = [ACD-A Rate × 20.6 mg/mL] ÷ [Patient Weight (kg)] Max Safe Rate: <1.5 mg/kg/min (standard) · <1.8 mg/kg/min (absolute max)
📖 Lee et al., Transfusion Med Rev 2012 · Weinstein et al., J Clin Apheresis 2023
⚠️

High-Risk Patients: Liver disease, hypoalbuminemia, hypomagnesemia, alkalosis, pediatric patients, and patients on calcium channel blockers are at elevated risk. Consider prophylactic calcium supplementation.

📊 Citrate Toxicity Assessment

ACD-A Infusion Rate
mL/min
Citrate Dose Rate
mg/kg/min
Toxicity Risk Level
based on dose rate
Recommended Ca²⁺ Supplement
prophylactic action
Citrate Dose Rate vs. Safe Threshold
0Safe (<1.5)Caution (1.5–1.8)Danger (>1.8 mg/kg/min)
SeveritySymptomsiCa²⁺ LevelManagement
MildPerioral tingling, paresthesias, chills0.9–1.1 mmol/LSlow blood flow rate, oral calcium carbonate
ModerateMuscle cramps, nausea, anxiety, tremors0.7–0.9 mmol/LReduce flow rate, IV calcium gluconate 1–2 g
SevereTetany, carpopedal spasm, arrhythmia, hypotension<0.7 mmol/LStop procedure, IV calcium gluconate 2–4 g, ECG monitoring
Lipoprotein Apheresis Calculator

LDL Apheresis Efficacy Live

Calculates acute LDL reduction per session and time-averaged LDL using the Kroon formula. Estimates treatment frequency needed to achieve target LDL levels.

LDL Reduction & Kroon Formula

Acute LDL Reduction (%) = (Pre-LDL − Post-LDL) / Pre-LDL × 100 Kroon Time-Averaged LDL = LDL_post + K × (LDL_pre − LDL_post) K = 0.73 (biweekly) · K = 0.63 (weekly) · K = 0.83 (monthly)
📖 Kroon et al., Atherosclerosis 1994
HoFH target: <100 mg/dL (ESC/EAS)

📊 LDL Apheresis Efficacy

Acute LDL Reduction
% per session
Time-Averaged LDL (Kroon)
mg/dL
Target LDL Achieved?
time-averaged vs. goal
Annual Sessions Needed
sessions/year
Patient TypeLDL ThresholdAdditional CriteriaASFA Category
HoFH — No CVDLDL ≥300 mg/dLMax tolerated drug therapyCat I, Grade 1B
HoFH — With CVDLDL ≥200 mg/dLMax tolerated drug therapyCat I, Grade 1B
HeFH — With CVDLDL ≥160 mg/dLFailure of drug therapyCat II, Grade 1B
Elevated Lp(a) — With CVDLp(a) ≥60 mg/dLProgressive CVD despite LDL controlCat II, Grade 2C
Plasma Exchange Calculator

Replacement Fluid Calculator (TPE)

Calculates albumin and FFP volumes required for a TPE procedure, estimates coagulation factor depletion with albumin-only replacement, and determines FFP unit requirements.

Replacement Fluid Formulas

Total Replacement Volume = TPV × Exchange Factor (1.0–1.5) Albumin Volume (mL) = Total Vol × Albumin Fraction FFP Volume (mL) = Total Vol × FFP Fraction FFP Units = FFP Volume ÷ 250 mL/unit Coag Factor Residual (albumin-only) = e^(−exchange vol / TPV) × 100
📖 Cervantes et al., AJKD 2023 · Zrimsek et al., J Clin Med 2024 · ASFA 9th Edition
From Patient Body Parameters or manual entry
Remainder = FFP. Min 70% albumin recommended (AJKD 2023)

💧 Replacement Fluid Prescription

Total Replacement Volume
mL
Albumin Volume
mL
FFP Volume
mL
FFP Units Needed
units (÷ 250 mL/unit)
Coag Factor Residual
% remaining after exchange
FFP Threshold Warning
clinical alert
IndicationPreferred FluidRationaleASFA Guidance
TTP (ADAMTS13 deficiency)100% FFP or cryopoor plasmaReplenishes ADAMTS13Cat I, Grade 1A
HUS (Shiga toxin)FFP or albuminLess clear benefit; albumin acceptable if no coagulopathyCat III, Grade 2C
ANCA-AAV / Anti-GBM5% AlbuminNo coagulation factor replacement neededCat I–II
Myasthenia Gravis / CIDP5% AlbuminStandard; FFP only if coagulopathy presentCat I, Grade 1B
Coagulopathy / Pre-surgical50–100% FFPMaintain coagulation factors ≥40% activityInstitutional protocol
Selective Apheresis Calculator

Immunoadsorption (IA) — IgG Removal

Calculates IgG removal per session and cumulative removal across multiple sessions using Protein A or other immunoadsorption columns.

Immunoadsorption IgG Removal

IgG Removed per Session (g) = [IgG] (g/L) × TPV (L) × Removal Rate Residual IgG after N sessions = IgG₀ × (1 − Removal Rate)^N Cumulative Removal % = (1 − (1 − r)^N) × 100
📖 Süfke et al., Ther Apher Dial 2017 · Giszas et al., Ther Apher Dial 2023
From Patient Parameters or manual entry

🔬 Immunoadsorption Results

IgG Removed (Session 1)
grams
Post-Session 1 IgG
g/L
Post-Final Session IgG
g/L
Cumulative Removal
% of baseline IgG
Total IgG Removed
grams total
Target IgG Achieved?
vs. goal
IndicationTarget MoleculeColumn TypeASFA Category
Myasthenia Gravis (severe)Anti-AChR / Anti-MuSK IgGProtein A or tryptophanCat I, Grade 1C
ANCA-AAV (refractory)ANCA (IgG)Protein ACat II, Grade 2C
Dilated CardiomyopathyAnti-β1-AR IgGProtein ACat II, Grade 1B
Pemphigus VulgarisAnti-Dsg1/3 IgGProtein A or IACat II, Grade 1C
Hemophilia A (inhibitors)Anti-FVIII IgGProtein ACat II, Grade 2C
Selective Apheresis Calculator

Double Filtration Plasmapheresis (DFPP)

Calculates sieving coefficient, removal ratio, and discard volume for DFPP. Selectively removes large-MW proteins (IgG, IgM, fibrinogen) while retaining albumin.

DFPP Sieving & Removal Formulas

Sieving Coefficient (SC): SC = C_filtrate / C_feed plasma Removal Ratio (RR): RR = 1 − (C_post / C_pre) Discard Volume: V_discard = V_plasma filtered × (1 − SC_albumin) Albumin Loss: Loss = Plasma filtered × [Albumin] × (1 − SC_albumin)
📖 Evaflux 4A default SCs: IgG 0.40 · IgM 0.05 · Fibrinogen 0.20 · Albumin 0.85
Typically 1.0–1.5× TPV per session

🔁 DFPP Sieving Results

IgG Removal Ratio
% removed per session
IgM Removal Ratio
% removed per session
Albumin Retained
% retained
Fibrinogen Removal
% removed
Estimated Discard Volume
mL (replace with 5% albumin)
Albumin Loss
grams
Safety Calculator

Extracorporeal Volume (ECV) Safety Check Live

Determines whether circuit priming is required based on the extracorporeal volume as a percentage of the patient's total blood volume. Critical for pediatric and small-volume patients.

ECV Safety Threshold

ECV% = (Circuit ECV mL / Patient TBV mL) × 100 Safe: ECV ≤10% TBV — no prime needed Caution: ECV 10–15% TBV — consider priming Mandatory Prime: ECV >15% TBV — prime required

In pediatric patients, pRBC prime is mandatory when ECV >15% TBV. In adults, 5% albumin or NS is acceptable.

📖 Schwartz et al., J Clin Apheresis 2016 · ASFA Pediatric Apheresis Guidelines
For Nadler formula; leave blank for simplified

🛡️ ECV Safety Assessment

Patient TBV
mL
ECV as % of TBV
% (threshold: 10–15%)
Circuit ECV
mL
Prime Decision
clinical recommendation
Photopheresis Calculator

Extracorporeal Photopheresis (ECP)

Calculates Uvadex® (8-MOP) dose, treatment volume, and eligibility check for ECP procedures. Supports both inline (Therakos® CELLEX®) and offline (Spectra Optia cMNC) methods.

Uvadex Dosing Formula (FDA-Approved)

Uvadex Dose (mL) = Treatment Volume (mL) × 0.017 8-MOP Concentration = Uvadex Dose × 20 mcg/mL × 1000 / Treatment Volume Target: 200 ng/mL in the buffy coat layer

Uvadex = 20 mcg/mL methoxsalen. The 0.017 factor is the FDA-approved dosing constant for the CELLEX system. Minimum eligibility: Hgb >10 g/dL, PLT >20×10⁹/L, weight ≥20 kg (inline).

📖 Therakos CELLEX PI · FDA Label for Uvadex · ASFA 9th Edition Cat I (CTCL), Cat II (GvHD)
Eligibility threshold: >10 g/dL
Eligibility threshold: >20×10⁹/L
Eligibility threshold: ≥1.0×10⁹/L
CELLEX default: 240 mL
For MNC dose/kg estimate

☀️ ECP Prescription Results

Uvadex Dose
mL (add to treatment bag)
Treatment Volume
mL
8-MOP Concentration
ng/mL (target: 200 ng/mL)
Eligibility Check
standard criteria
Recommended Device Setting
device-specific
IndicationASFA CategoryGradeNotes
CTCL (Erythrodermic MF/SS)I1BFirst-line for erythrodermic stage
Acute GvHD (steroid-refractory)II2CSecond-line; used with steroids
Chronic GvHDI1BWell-established; skin, liver, lung
Cardiac Transplant RejectionII1BProphylaxis and rejection treatment
Lung Transplant — BOSII1CBronchiolitis obliterans syndrome