How to compare pricing for flow cytometry CROs

You just had your IND approved. Now it’s time to look at pharmacodynamic measures. At this point, you want to compare different flow cytometry options. You come back with quotes from two vendors, with these prices per specimen for a gated panel.

Vendor 1: $800
Vendor 2: $1,250

Naive method

Which price is better? Well, this isn’t a trick question: $800 is cheaper than $1,250. $1,250 is 56% more expensive than $800. So yes, Vendor 1 is a better deal. This is the naive way of comparison.

Panel	Cost per specimen
8 marker panel	$800
25 marker panel	$1,250
% Change from 25 to 8	56%

But what if we told you Vendor 1’s panel had 8 markers, and Vendor 2’s panel had 25 markers?

Per marker method

Now, you might compare on a per marker basis.

This is a better way to compare. In this case, you would get $100 per marker for Vendor 1, and $50 per marker for Vendor 2. And in this case, the 25 marker panel is 50% lower than the 8 marker panel.

Panel	Cost per specimen	Number of markers	Price per marker
8 marker panel	$800	8	$100
25 marker panel	$1,250	25	$50
% Change from 25 to 8	56%		-50%

But, you’re a drug developer and you care about detail in the immune state. You know the immune state means that the more markers you have on your panel, the greater “depth” you can capture in your immune lineage or “tree.”

Price per subset method

That brings us to price per subset.

The 8-marker panel yields 52 subsets while the 25-marker panel produces 298 subsets. This difference dramatically changes the cost-benefit tradeoff. All you need to do is divide the headline price by the number of subsets.

Calculating price-per-subset

Panel 1: $800 / 52 subsets = $15.38 per subset
Panel 2: $1,250 / 298 subsets = $4.19 per subset

Let’s see that table again. Now, we can see that using price per subset, the 25 marker panel posts a 73% improvement, compared to an 8 marker panel.

Panel	Cost per specimen	Number of markers	Price per marker	Number of subsets	Price per subset
8 marker panel	$800	8	$100	52	$15.38
25 marker panel	$1,250	25	$50	298	$4.19
% Change from 25 to 8	56%		-50%		-73%

A simple change in the denominator yields striking differences in the affordability for each panel. Of course, price isn’t the only attribute that matters, but it’s an essential variable that drug developers care about when picking a flow cytometry provider.

How can you use this measure?

If you get different flow cytometry quotes, you might want to use this calculation to get an apples-to-apples comparison.

Are there any limitations to the measure?

This measure just focuses on similar outputs like FCS and gated files. That is, it assumes both methods generate similar outputs. But realistically, drug developers don’t just stop at an FCS file. They need to invest the time or money to turn the FCS file into statistically significant differences. So, this measure doesn’t account for the bioinformatics time or money to turn these FCS files into a true analysis.

Moreover, this measure doesn’t capture sample failure rates, which can impact the actual cost per usable subset. For example, if 10% of samples fail before they even hit a machine with one panel, that would increase your cost per subset downstream.

In sum

The price-per-subset metric is a more realistic way to compare cytometry services. Cytometry’s value is to read more and more detail of the immune “tree”, and by using this measure, you can make better apples-to-apples comparisons between cytometry panels.

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