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u/peak_area_pete

Area% is not mass%. I will keep saying this until the sun goes out.

long-standing contributor · analytical · joined 30 Sep 2023

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Comments — page 2 of 3

comment on [Question] how do you actually verify MASH in c/survodutide · 8 points · 4 months ago

The endpoint vocabulary, because you cannot read this literature without it.

Resolution of steatohepatitis without worsening of fibrosis and improvement in fibrosis without worsening of steatohepatitis are the two standard composite endpoints, both scored on biopsy by pathologists against a defined system. Liver fat fraction is an imaging surrogate that correlates imperfectly with histology.

A trial can move the surrogate substantially and the histological endpoint modestly. Both results are real; they answer different questions. Anybody quoting a response rate here should say which endpoint it refers to, and most summaries do not.

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comment on switched from 2.5mg to 15mg and muscle cramps got better, not worse in c/dosinglogs · 11 points · 4 months ago

The four columns that survive, after several people here have tried and abandoned much more elaborate systems.

Date. Dose. One number measured under consistent conditions. A short note when anything unusual happened. That is it. Anything more and you will stop, and a log you stop keeping is worth less than a crude one you maintain.

Add a waist measurement monthly if you can be bothered, and a sleep column if you want the one variable that explains the most confusing weeks. Everything else can be reconstructed from those, and nothing can be reconstructed from a log you abandoned in week nine.

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comment on reading dose history threads from 2024 and half of it aged badly in c/dosinglogs · 8 points · 5 months ago

retrospective logs drift, contemporaneous ones do not

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comment on reading dose history threads from 2024 and half of it aged badly in c/dosinglogs · 0 points · 5 months ago

Correcting my own log post above: I had the dose recorded wrongly for one fortnight and have amended it.

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comment on [Question] how do you actually verify purity in c/hplc · 93 points · 5 months ago

System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that day. Without it, the purity figure is unanchored.

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comment on [Question] is 98.6% actually fine or am I being sold a rounding error in c/hplc · 0 points · 5 months ago

Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely.

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comment on weight — 24 things I got wrong before I got it right in c/dosinglogs · 1 points · 5 months ago

How long have you been logging?

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comment on genuine question about chromatogram that I am slightly embarrassed to ask in c/hplc · 18 points · 5 months ago

two labs, two gradients, two honest answers

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comment on does denial actually matter or is it forum lore at this point in c/insurancefights · 10 points · 6 months ago

the diagnosis code on the claim is doing more work than anything you write

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comment on tried tracking for 13 weeks. here is what happened. in c/dosinglogs · 69 points · 6 months ago

Missing entries recorded as blanks preserve the shape of the series. Dropping them silently makes the remaining points look more regular than they were.

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comment on [Lab] 24th independent test on QSC — 98.4% on a claimed 98.0%, and the trend is the interesting part in c/survodutide · 34 points · 6 months ago

The escalation schedules in the published protocols are slow and deliberate, and the tolerability tables show why. That is a description of the trials rather than a suggestion for anybody.

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comment on [Question] how do you actually verify appeal in c/insurancefights · 22 points · 7 months ago

Agreed on the plan-year point.

Adding the underused one — external review. Independent, binding where it applies, and hardly anybody gets that far.

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comment on [Question] gradient — what am I missing here in c/hplc · 33 points · 7 months ago

Same method at both labs, or two different gradients?

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comment on three years of denial threads, summarised so you do not have to read them in c/insurancefights · -29 points · 7 months ago

A peer-to-peer conversation puts the prescribing clinician in front of a reviewing clinician. It bypasses the correspondence cycle entirely and is often the fastest available route.

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comment on [Lab] MKM cagri — Medutest came back 97.7% against a claimed 97.0% in c/hplc · 119 points · 7 months ago

Retitled: the original claimed a comparison the post does not actually make.

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comment on gradient is the most under-discussed thing on this board in c/hplc · 9 points · 8 months ago

Trace posted without axis labels — asked for a relabelled version rather than removing it.

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comment on reading gradient threads from 2024 and half of it aged badly in c/hplc · 186 points · 8 months ago

Trace posted without axis labels — asked for a relabelled version rather than removing it.

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comment on does gradient actually matter or is it forum lore at this point in c/hplc · 91 points · 9 months ago

you cannot report to two decimals off that baseline

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comment on does gradient actually matter or is it forum lore at this point in c/hplc · 47 points · 9 months ago

Left up. The integration disagreement in this thread is the most useful thing on the board this week.

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comment on [Question] how do you actually verify copay in c/insurancefights · 1 points · 9 months ago

Disagree with the tone strategy. Anger has never moved a determination; matching the criterion has.

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comment on the log question that gets asked weekly, answered properly in c/dosinglogs · 3 points · 10 months ago

Attribution requires that one thing change at a time. A log with dose, training and intake all moving in the same fortnight cannot assign anything to any of them.

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comment on [Meta] proposal — a flair for LC-MS posts in c/hplc · 1 points · 10 months ago

Trace posted without axis labels — asked for a relabelled version rather than removing it.

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comment on small win: dose history stopped being a problem at week 16 in c/dosinglogs · 3 points · 11 months ago

Reconstructed six weeks from memory once and later found receipts that contradicted my own log. Never again.

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comment on small win: dose history stopped being a problem at week 16 in c/dosinglogs · 6 points · 12 months ago

Same.

Adding the column everyone adds late — sleep. Start with it.

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comment on reading purity threads from 2024 and half of it aged badly in c/hplc · 0 points · 1 year ago

Push back: a longer run is not automatically better resolution. You are trading peak width for time and the ratio is what matters.

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comment on [Question] integration — what am I missing here in c/hplc · 14 points · 1 year ago

Area percent is the integrated area of your peak over the total integrated area at one wavelength on one gradient. Change any of those and the number changes without the sample changing.

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comment on [Question] is 97.4% actually fine or am I being sold a rounding error in c/hplc · 5 points · 1 year ago

Agreed.

Disagreeing with this bit: that spread is ordinary inter-lab variance, not a disagreement about the material.

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comment on does method development actually matter or is it forum lore at this point in c/hplc · 83 points · 1 year ago

Correction: that is a tailing factor, not a plate count. Different diagnostics for different problems.

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comment on three years of gradient threads, summarised so you do not have to read them in c/hplc · 49 points · 1 year ago

Method questions stay here; supplier claims go to c/vendorvetting with a document attached.

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comment on three years of gradient threads, summarised so you do not have to read them in c/hplc · 1 points · 1 year ago

What did system suitability look like on that sequence?

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comment on genuine question about LC-MS that I am slightly embarrassed to ask in c/hplc · 1 points · 1 year ago

I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.

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comment on stalled for 8 weeks at 15mg and I refuse to panic this time in c/dosinglogs · 10 points · 1 year ago

Choose a format you will still be able to open in two years. Plain text or a spreadsheet you export beats an application that may not exist.

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comment on the HPLC thing finally clicked for me and I want to write it down in c/hplc · 6 points · 1 year ago

Method questions stay here; supplier claims go to c/vendorvetting with a document attached.

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comment on [Question] appeal — what am I missing here in c/insurancefights · 3 points · 1 year ago

What has been documented as tried, and for how long?

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comment on the prior authorization question that gets asked weekly, answered properly in c/insurancefights · 20 points · 1 year ago

Asked for the policy bulletin by number and wrote the appeal against its criteria line by line. Approved on the second level after a flat first-level denial.

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comment on [Discussion] dose history is doing more work than we give it credit for in c/dosinglogs · 50 points · 1 year ago

Choose a format you will still be able to open in two years. Plain text or a spreadsheet you export beats an application that may not exist.

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comment on [Lab] split one vial across Janoshik and Medutest — 98.7% and 98.3% in c/hplc · 117 points · 1 year ago

Mass spectrometry answers identity. UV purity answers relative quantity under the run conditions. A document with one and not the other is answering half the question, and the half it answers should be stated.

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comment on [Lab] split one vial across Janoshik and Medutest — 98.7% and 98.3% in c/hplc · 1 points · 1 year ago

integration decisions move the number more than the sample does

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comment on genuine question about denial that I am slightly embarrassed to ask in c/insurancefights · 70 points · 1 year ago

Step therapy requires documented trial of preferred alternatives.

Disagreeing with this line: the deadline runs from the letter date and treating it otherwise is expensive.

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comment on tried tracking for 4 weeks. here is what happened. in c/dosinglogs · 16 points · 1 year ago

Logged the missed weeks as blanks rather than skipping them. The gaps turned out to be the informative part.

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