Why scientists need a procurement model
If you can’t explain total cost of ownership (TCO) in lab terms, procurement will do it for you – poorly. For leukopaks and PBMC work, the cheapest unit price can be the most expensive project when repeats, delays, and QC fails pile up. A clear TCO model helps you choose the input that produces the most usable cells for the least money and time.
Define “usable cell” for your context
- Viable post – thaw and within your acceptance window.
- Phenotypically appropriate (subset ratios, markers).
- Functionally ready for the next assay step (not just alive).
Your TCO should be built on cost per usable cell, not per purchased cell.
List the cost buckets
- Acquisition: unit price, shipping, rush fees.
- Processing: staff time, reagents, consumables, instrument time.
- Failures and repeats: discount rate for QC fails; re – run costs.
- Delays: cost of missed sprint days or idle instruments.
- Inventory carrying (for cryo strategies): storage, monitoring.
- Documentation: time spent chasing CoA, donor data, and chain – of – custody.
Where recallable donors lower TCO
- Fewer repeats caused by donor variability.
- Predictable procurement reduces rush shipping and off – hours staff time.
- Faster QA review when the documentation looks the same lot after lot.
Fresh vs. cryo in a TCO lens
- Fresh may have lower per – lot acquisition cost but higher schedule risk; a single delay can burn staff hours, facility, and instrument time.
- Cryo adds storage cost but enables planned repetition and better instrument/facility utilization. If you schedule thaws on fixed days, your per – assay overhead drops.
Build a simple calculator
- Input: unit price, shipping, expected viability, expected recovery, % QC fail rate, staff hourly rate, reagent cost per run, instrument/facility hourly rate, repeat probability, storage/month (if cryo).
- Output: cost per usable cell; scenario comparisons (e.g., new donor each time vs. recallable donor; fresh vs. cryo; regional processing vs. long – haul shipping).
Run three scenarios
- Lowest unit price + mixed donors + long transit.
- Mid – price + recallable donor + regional processing + cryopreservation.
- Premium price + bespoke handling + minimal storage.
The cheapest sticker price rarely wins when you total the repeats and delays.
Operational notes that shift TCO
- <30 – minute to process reduces later viability loss; that’s fewer repeats.
- A fixed thaw SOP prevents slow loss of cells to handling.
- A solid documentation pack (CoA + attributes + handling SOP) reduces meetings and QA cycles.
How to present this to non – scientists
One chart: “Cost per usable cell” across the three scenarios. One sentence: “The recallable donor + regional processing + cryo plan is X% cheaper per usable cell because we don’t pay for repeats, rush shipping, or idle instruments.”
Next steps
- Build the calculator (spreadsheet) with defaults you can defend.
- Plug in last quarter’s true numbers.
- Choose the path that gives the highest usable – cell yield at the lowest real cost, even if the unit price looks higher.
What do you get in the end?
You get a procurement plan that matches scientific reality. The program stops leaking time and money into the cracks you can’t see on a quote
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