Extended criteria (experimental). This is the broader ten-condition engine, kept as a secondary area. It shows ICD-10-CM codes and illustrative grouping effects for CDI staff. The primary surface is Before you sign (kidney, measurement only). All extended pages.

Acute blood loss anaemia

Rule blood_loss_anemia version 2026.11-1 · condition: Acute blood loss anaemia

Published source

WHO guideline on haemoglobin cutoffs to define anaemia in individuals and populations (2024). Adult cut-offs: men <13 g/dL, non-pregnant women <12 g/dL (unchanged from 2011). https://thebloodproject.com/definition-of-anemia-hb-thresholds/ · public page checked 2026-11-14

WHO PDF not loadable during verification; thresholds verified from a secondary page citing it.

Also: ISTH definition of major bleeding in non-surgical patients (Schulman and Kearon, J Thromb Haemost 2005;3:692-694) (2005). Fall in haemoglobin of 2 g/dL or more, or transfusion of 2 or more units. link

Contested or local convention. There is no published clinical definition of "acute blood loss anaemia". This rule is a LOCAL CONVENTION: WHO anaemia threshold at the nadir, a documented bleeding source, and an acute fall of >=2 g/dL OR >=2 units transfused (borrowed from the ISTH major-bleeding definition, which secondary restatements word inconsistently as AND/OR).

Inputs

sex: Sex
hgb_first: First haemoglobin this stay (g/dL)
hgb_nadir: Lowest haemoglobin this stay (g/dL)
hgb_drop: Highest value before the nadir minus the nadir (g/dL)
prbc_units: Red cell units transfused
bleeding_documented: A bleeding source quoted from a note, or a bleeding principal diagnosis

Thresholds

t.hb_m: 13
t.hb_f: 12
t.drop_major: 2.0
t.drop_min: 1.0
t.prbc_major: 2

Derived values

Evaluated in order
Name	Expression
anaemic	`case(sex == 'M', hgb_nadir < t.hb_m, sex == 'F', hgb_nadir < t.hb_f, null)`
acute_fall	`hgb_drop >= t.drop_major or prbc_units >= t.prbc_major`

Outcomes

First true outcome wins; an unknown input makes an outcome unknown
Outcome	When	Status	Supports
met Haemoglobin fell {hgb_drop} g/dL to {hgb_nadir} with {prbc_units} unit(s) transfused and a documented bleeding source	`bleeding_documented and anaemic and acute_fall`	supported	D62 Acute blood loss anemia
anaemia_only Anaemia (nadir {hgb_nadir}) without an acute fall or transfusion	`anaemic and hgb_drop < t.drop_min and prbc_units == 0`	supported	D64.9 Anemia (acute blood-loss criteria not met)
not_anaemic Haemoglobin nadir {hgb_nadir} g/dL is above the WHO anaemia threshold	`present(hgb_nadir) and not anaemic`	not_supported	—
no_source Acute haemoglobin fall without a documented bleeding source	`anaemic and acute_fall`	judgement	—
borderline Haemoglobin fell {hgb_drop} g/dL without transfusion (between 1 and 2 g/dL)	`anaemic`	judgement	—

ICD-10-CM specificity ladder (FY2026 CC/MCC status as a secondary diagnosis)

D64.9 Anemia, unspecified · non-CC
D62 Acute posthemorrhagic (blood loss) anemia · CC (refines D64.9)

Query topic: hematology documentation · prompts for an undocumented diagnosis: yes

Where clinical judgement is required

Expected operative blood loss versus acute blood loss anaemia is a clinician judgement the rule does not make.