The most rational approach might be to report to a level of significance
that is reflected in the confidence limits for the measurement. Doug Hirst
may remember that we tried this once at King's and no one understood it.
The practical problem with reporting data using a level of significance
that reflects the analytical precision is that this can mislead users who
forget that biological variation is likely to be greater than analytical
variation and may ascribe inappropriate clinical significance to the
difference between a result and a reference value or a previous result in
the same patient.
WM
At 15:55 03/07/2002 +0100, Graham Mould wrote:
>Following from the discussion about HDL measurements, I notice that most
>of the HDL results reported by laboratories are to one place of decimal.
>We are conducting a clinical trial (for an Americian company) where I have
>been asked to ask our laboratory to report to two places of decimal. The
>Americians argue that an increase from 35 to 40mg/dL is more significant
>than going from say 1.0 to 1.1 mmol/L. The laboratory, quite correctly
>have suggested, that the assay may not be sensitive enough to go to two
>places accurately, although the triglycerides are reported to two places
>of decimal. What do other labs do?
>Graham Mould,
>Guildford Clinical Pharmacology Unit,
>Royal Surrey County Hospital,
>Egerton Road,
>Guildford, Surrey, UK
>GU2 7XX.
>Tel:44 (0)1483 406886.
>Fax: 44 (0)1483 455375.
>
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From: Dr William J Marshall
Reader and Hon Consultant in Clinical Biochemistry
GKT School of Medicine
London SE5 9PJ
UK
telephone: 020 7346 3275
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