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How many liters of medium a day does this perfusion run need?

Perfusion CSPR and perfusion rate calculator

From the medium each cell uses per day (CSPR) and the cell density, works out the daily medium flow in a perfusion culture, how many vessel volumes that is per day (VVD), and the total medium and cost for the run.

When to use itUse it when planning a perfusion run, to estimate how much medium to prepare and what it will cost.

Prefilled with an example: a 2 L vessel held at 50 × 10⁶ cells/mL for 15 days. Change any value and the result updates.

pL/cell/day

For CHO cells, values of about 20 to 50 pL/cell/day are often quoted (it depends on conditions). Start high and bring it down as you watch the culture.

×10⁶ cells/mL

The cell density you want to hold. 50 means 50 million cells per mL.

L

The liquid volume actually in the bioreactor.

days

Used for the total medium over the run.

per L

For the cost estimate. The example uses 3,000 yen per liter; enter your own price and read the cost in the same currency. Enter 0 to skip.

Daily medium flow (perfusion rate)3 L/day
Vessel volumes per day (VVD)1.5 /day
Total medium for the run45 L
Medium cost (estimate, in your currency)135,000

Holding this cell density takes 3 L of medium a day (1.5 vessel volumes). Over 15 days that is 45 L, costing about 135,000 at your price per liter. One to five vessel volumes a day is a common range for mammalian cells.

Guide to medium exchange per day (VVD)

The row that matches your result is marked.

  • Less than 1 vessel volume a dayLowMammalian perfusion often runs at 1 to 5 vessel volumes a day, and this is below that. Too little exchange starves the cells and lets lactate and ammonia build up. Check by measurement that the CSPR is not too low. This is not a fixed standard.
  • 1 to 5 vessel volumes a dayYour resultCommon rangeThe range our related article describes as typical for mammalian cells (roughly 1 to 5 VVD). It shifts with cell line, medium and product, so refine it while watching growth, viability and metabolite data.
  • More than 5 vessel volumes a dayHighMedium costs climb and the harvest gets more dilute. There is room to revisit the cell density or the CSPR. The range varies with conditions and is not a single standard.
  • Setting the CSPRStart high, lower graduallyDo not aim for a low value straight away; start from a safe, higher setting. Lower it while watching growth, viability, cell size, glucose, lactate, ammonia and amino acids, and settle just before any of them starts to slip.

How it is calculated

Daily medium = CSPR × cell density × working volume. The unit conversions (pL to L, ×10⁶ cells/mL to cells/mL, L to mL) are done inside, and together they leave the factor 10⁻³. The calculation assumes the cell density and working volume stay constant through the run.

perfusion rate [L/day] = CSPR × VCD × working volume × 1e-3 VVD = perfusion rate ÷ working volume

Source: The standard perfusion design equation, which sets the perfusion rate from the cell-specific perfusion rate (CSPR).

With your numbers

  1. perfusion rate = CSPR × VCD × working volume × 10⁻³ = 30 × 50 × 2 × 10⁻³ = 3 L/day
  2. VVD = perfusion rate ÷ working volume = 3 ÷ 2 = 1.5 /day
  3. total medium = perfusion rate × run days = 3 × 15 = 45 L

Limits of this calculation

  • The guide values for CSPR (20 to 50 pL/cell/day for CHO, somewhat higher for HEK293) and 1 to 5 vessel volumes a day vary with conditions. Do not apply them to your process as is; use them as a starting point and confirm by measurement.
  • The equation is a simple product that assumes a constant CSPR (perfusion rate = CSPR × cell density × volume). It does not capture changes in nutrient uptake, the nutrient design of the medium, or by-product accumulation.
  • Cell density is taken as ×10⁶ cells/mL, and the unit conversions (pL to L, mL to L) are done inside. Entering the wrong unit shifts the result by orders of magnitude.
  • Cost is only unit price × total volume. Labor, equipment and the effect of a more dilute harvest are not included.
  • Flows from cell bleed and harvest, and changes in cell density from growth, are not considered; the daily volume is simply added up. Changes in density during the run are not reflected.

Primary sources

Every calculator gives an estimate for learning, built on published information and primary sources. Real decisions follow the applicable guidance and expert judgment.