Phage Lab Calculators

Six calculators for the phage lab, built for the bench in the Tarleton State University SEA-PHAGES lab and the Virus Isolation Course. Each one shows every step of its arithmetic, so a result can be checked by hand and copied into a lab notebook, and each page states its formula and a fully worked example, from the lab's notebooks where they have one.

The calculators#

• Titer calculator: pfu/ml from a plaque count, the volume plated and the dilution, for a full plate titer or a spot titer.
• Serial dilution planner: the tubes that take a lysate from its titer to a target concentration, with the volume to carry and the buffer for each.
• Webbed plate calculator: the lysate and dilution to plate for webbed plates from a lysate of known titer, and the lysate you get back from flooding them.
• Lysate volume planner: how much lysate a set of plates uses in all, and how to mix it with buffer to plate.
• MOI calculator: the multiplicity of infection from a titer, the volume added and a host cell count, and the share of cells infected.
• Efficiency of plating calculator: how well a phage plates on a test host against a reference host, from two titers or from plaque counts.

Where the formulas come from#

The titer, dilution and webbed plate formulas are the ones worked through question by question in Lab Calculations and Common Questions; the MOI and efficiency of plating calculators use the standard definitions, stated on their pages; and the lab's own settings (volumes plated, spot volumes, flood yields) come from the Phage Isolation and Purification Protocol, which each calculator cites where it uses one.

Titers from several plates#

For titers from three or more plate counts, with trimmed means, confidence intervals and efficiency of plating, use Stephen Abedon's Titering and EOP Calculator. These calculators take one count at a time and show the arithmetic instead.