The Retest Cadence

The audit runs quarterly, but blood should not be drawn quarterly. Markers move on different clocks — glucose in hours, A1c over months — and testing at the wrong frequency adds cost and noise without adding signal. This page maps which markers deserve which frequency, when a sooner draw is actually justified, and how to keep every comparison honest.

Why the Audit Is Quarterly and the Draw Is Not

The Quarterly Audit repeats on a three-month loop because several of its measures genuinely change that fast: weight, waist, grip, home blood pressure, and sleep regularity move week to week, and re-measuring them quarterly is how a trend becomes visible. Blood markers live on longer clocks — weeks to months — so a quarterly draw would mostly re-snapshot the same biology at four times the cost.

• ⚖️ Frequency should match the signal's speed: the fast-moving audit measures are the Body Metrics — waist, grip, weight — not the lab panel.
• 🩺 Home blood pressure is the quarterly blood marker: it moves on days and needs frequent home readings; the Blood Pressure Protocol owns that cadence, and it is a home measurement, not a draw.
• 🧪 The lab layer is the annual layer: once a year, same quarter, same lab — that rhythm is enough to catch the markers that actually drift.

The parent Blood Markers guide and the Quarterly Audit series lead both say it plainly: these markers move on month-timescales, and more frequent draws add noise, not signal.

The Timescale Ledger

Each marker carries its own reflect window — how long before a real change shows up in the number.

The Baseline First

Cadence assumes a starting point. The first draw is not just a data point; it establishes the row that every later comparison leans on — the Tracking Sheets page's four-column log: this year, last year, the lab, the context. Without that first row there is no trend, and without a trend a single value is nearly unreadable.

• 🌱 Do the baseline once, properly: same lab, morning, real fast, nothing heroic the day before — a clean first row is worth more than three rushed ones.
• 🗓️ Pin the draw quarter: choose the same audit quarter every year; seasonal weight, activity, and diet drift otherwise become false signals.
• 🔁 Re-baseline when the lab changes: switching labs or assays invalidates the comparison; the first new-lab year becomes a fresh row, not a "crash" or a "win" (the Trend-Reading Method page details this trap).

One nuance belongs here: the baseline is not a test you pass or fail. The point of the first row is simply that every later row has something to lean on. If your first draw lands outside the usual bands, that is not a judgment on you — it is the most useful starting point the audit could have, because it sets the direction question every following year answers.

Signals That Justify a Sooner Draw

Annual is the steady-state cadence, not a ceiling. A handful of situations legitimately pull the next draw earlier — and in nearly every case the driver is a clinician's decision, not personal impatience.

• 💊 A medication start or dose change: new statins, metformin, or blood-pressure drugs come with their own monitoring seesaw; the prescriber sets the 4-to-12-week checks (see the Medication & Supplement Reconciliation parent for the conversation).
• 🚩 A prediabetes or borderline finding: an A1c in the 5.7–6.4% band or a fasting glucose in the 100–125 range earns a 3-to-6-month follow-up — the reversible window rewards a short loop.
• 🧭 A major lifestyle change under clinician guidance: after meaningful weight loss or a structured intervention, a three-month re-check shows what actually registered, because that is the shortest window a moving marker can answer.
• 🆕 New symptoms or family-history changes: symptoms earn a visit, and the visit may order the draw — the lab follows the evaluation, not the other way around.
• 🩺 At the clinician's request after a new diagnosis or a medication interaction question: monitoring tied to a specific concern follows the concern's timeline, not the calendar.

The Rules That Keep Comparisons Honest

Frequency is half the cadence; consistency is the other half. Every guideline's interval assumes the numbers it compares were collected the same way.

• 🏥 One lab, one method: assays differ slightly between labs and machines, so a 10 mg/dL move can be equipment, not biology; the parent guide's same-lab rule is the fixed condition of every comparison.
• 🌅 Same morning, same fast: draw early, after the same eight-to-twelve-hour fast, every year — coffee stays out of the morning routine on draw day.
• 📝 Log the context column: illness, travel, stress, a steroid course, or a new supplement in the two weeks before the draw all belong in the row; the log is what turns a number into a question.
• 🧾 Non-fasting lipids are acceptable when that is your lab's convention: the flagging rules exist (Nordestgaard et al., European Heart Journal, 2016) — but the convention must be the same year to year, or the trend line lies.

When the Cadence Itself Is the Question

If a clinician has not named a frequency, the honest default is: baseline once, then annual for the core four (ApoB, HbA1c, fasting glucose, lipids), with a sooner draw only after a change, a borderline finding, or a medication adjustment. The quarterly rhythm belongs to the non-blood measures — weight, waist, grip, home blood pressure, sleep — which is exactly what each annual row then lets you interpret: did the lifestyle trend move the lab trend, a year apart, same conditions? That pairing is the entire point of the audit: the quarterly row of lifestyle measures and the annual row of labs, compared under the same conditions, are what let a trend speak at all.

Questions About Timing, Answered Briefly

• ❓ Why not draw quarterly and just know more? Because knowing more is not the same as knowing better — slow markers re-sampled quarterly mostly repeat the previous quarter plus its noise, at four times the cost and a fifth of the patience.
• ❓ How soon after I start eating better should I re-check? About three months. A1c and ApoB need that window to reflect a real change; an earlier draw will predictably disappoint and can even mislead.
• ❓ My A1c moved from 5.6 to 5.8 in a year — do I need a six-month draw? Likely yes, and that is the clinician's call: the 5.7–6.4% prediabetes band conventionally earns a three-to-six-month follow-up precisely because the window is reversible.
• ❓ Does switching labs ruin my trend? It rebases it. The first new-lab year becomes a fresh baseline row; treat the transition as a new chapter rather than a crash or an improvement, and note the switch in the context column.
• ❓ Are non-fasting draws fine for my annual panel? When that is your lab's convention, yes — but the convention must match last year's, because mixing a fasting year with a non-fasting year is the fastest way to manufacture a false trend.

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