# HbA1c

> HbA1c is glycated haemoglobin, reflecting average blood glucose over roughly the preceding three months. It matters before surgery because poor glycaemic control is associated with higher rates of post-operative complications, particularly infection and impaired wound healing. Unlike a one-off glucose reading it cannot be improved quickly, so it has to be identified with weeks to spare.

*Source: https://getpathways.ai/glossary/hba1c*

Also known as: glycated haemoglobin, A1c, HbA1c test

- **Measures**: Average blood glucose over roughly the preceding three months
- **Perioperative concern**: Higher rates of post-operative infection and impaired wound healing
- **Modifiable**: Yes, but slowly — requires weeks to months, not days
- **Common gap**: Last confirmed result is months old, or only patient-reported

## Why the timescale matters more than the number

HbA1c is the one common pre-operative finding where the value of discovering it
early is unambiguous. A single high glucose on the morning of surgery is a
snapshot; an HbA1c reflects months, and moving it takes months.

That makes it the clearest illustration of the general point about
pre-operative timing. Identified at booking, poor control is an optimisation
window — a referral back to the GP or diabetes service with weeks in hand.
Identified at the pre-admission clinic three days before surgery, the same
finding is either a cancellation or a case that proceeds at avoidable risk.

## The two failure modes

**The result is stale.** A patient with diabetes may have an HbA1c on file, but
from eight months ago, before a change in circumstances or medication.

**The result is patient-reported.** "Around nine" is a genuinely useful signal
and a poor basis for a plan. It should be treated as a prompt to obtain a
current result, not as one.

Pathways handles this by listing what it does not know. An HbA1c that is
patient-reported or out of date appears explicitly under missing information on
the risk profile, with the confidence attached — the staged example shows a
patient-reported value at 0.86 confidence with "gap: recent HbA1c" recorded
alongside it, and nineteen days of optimisation window still available.