Three lab analytes stop at a reporting limit¶

Lactate is capped at 15.0 mmol/L, aPTT at 400.0 s, and ESR does not go below 2 mm/h: the values at the limit stand for "this or beyond", not for the number itself.


Status	likely: consistent, with a known gap.
Devices	Clinical records
Variables	Lactate, Activated partial thromboplastin time, Erythrocyte sedimentation rate

What it means¶

Treated as exact numbers, these values understate the most abnormal results: a lactate of "15" may be 20.

What is done about it¶

Treat them as censored (an open interval beyond the limit), as the registry does for ages above 89.

Detail¶

Analyte	Limit	Results at the limit	Cases	Most at any nearby value
Lactate	15.0 mmol/L (top)	317	28	16
aPTT	400.0 s (top)	226	87	8
ESR	2 mm/h (bottom)	89	72	32

Each limit holds many times more results than any neighbouring value, the pattern of an analyser's reportable range rather than of physiology.

Evidence¶

Study	Date	Status	Summary
Heaping screen of all variables	2026-10-13	current	Every hand-entered clinical value and every lab analyte was screened for mixed resolution and heaping, to decide which need a rounding model and which need only a registry entry.