lal_assay

The test is cheap relative to the material and slow relative to nothing. A kinetic chromogenic determination is under an hour of instrument time.

Absence of a figure is not a low figure. The two are different statements and the index does not let one stand in for the other anywhere on this site.

No endotoxin figure on this record, which is true of roughly three quarters of the index. It is the one measurement that cannot be inferred from any other and the one most often omitted.

The index aggregates endotoxin over the quarter of records that carry a figure and states the denominator every time. That is the only honest way to publish a partial coverage statistic.

What this record does establish is on the page and it is substantial. What it does not establish is listed under the provenance block rather than left for the reader to infer.

Reading the record the same way.

I am sceptical of unstated methods generally and of unmeasured properties specifically. This is the second kind, and it is the more honest of the two failure modes.

Spike recovery on the sample matrix is the control that distinguishes a real result from an inhibited one. It is not reported here.

Recombinant factor C would sidestep the reagent supply constraint entirely and correlates well. Nothing in this market uses it.

The index records the absence rather than imputing a value. An unmeasured property is unmeasured, and the specification block above says so explicitly.

Where a laboratory offers the test as an add-on, the marginal cost on an existing submission is small. That is the cheapest route to closing this gap and it is available on most submissions here.

An index that imputed a value here would be inventing data. Publishing the absence is less satisfying and considerably more useful.