The GOLD MARK Mnemonic — Modern HAGMA Causes

What does GOLD MARK stand for?

GOLD MARK expands to Glycols, 5-oxoproline (pyroglutamic acid), L-lactate, D-lactate, Methanol, Aspirin (salicylates), Renal failure, and Ketoacidosis. It is the mnemonic many critical-care and nephrology services now prefer for the workup of a high anion gap, because it keeps the toxin list current and surfaces causes that the older MUDPILES mnemonic omits. Use the anion gap calculator to confirm the gap, then walk GOLD MARK to organize the differential for high anion gap metabolic acidosis (HAGMA).

GOLD MARK is a modern mnemonic for the causes of high anion gap metabolic acidosis — Glycols (ethylene, propylene, diethylene), 5-oxoproline (pyroglutamic acid), L-lactate, D-lactate, Methanol, Aspirin, Renal failure, and Ketoacidosis. It updates MUDPILES by adding D-lactate and pyroglutamic acid while dropping cyanide, paraldehyde, and formaldehyde, which are now rarely seen.

The eight letters, one by one

Why GOLD MARK updates MUDPILES

The classic MUDPILES mnemonic was codified in an era when paraldehyde, cyanide, and formaldehyde ingestions were more common and D-lactate was not yet a recognized clinical entity (Kraut & Madias, CJASN). Modern ICU and emergency practice has shifted the landscape. GOLD MARK makes four meaningful changes:

• Adds the glycols as one family (G) — ethylene glycol, propylene glycol, and diethylene glycol share alcohol dehydrogenase metabolism and the same high-AG/high-osmolar-gap signature, so they belong together rather than scattered across "P" and "E".
• Adds 5-oxoproline (O) — pyroglutamic acidosis is a real, easily missed cause seen in malnourished women on chronic acetaminophen, in patients on flucloxacillin or vigabatrin, and in severe glutathione depletion.
• Splits L- and D-lactate (L, D) — the routine lactate assay measures only the L-isomer. D-lactic acidosis from short-bowel syndrome produces an unexplained high anion gap unless a D-lactate is specifically ordered.
• Drops the obsolete toxins — cyanide, formaldehyde, and paraldehyde remain physiologically valid causes of HAGMA but are vanishingly rare today; keeping them on the bedside mnemonic dilutes recall without improving diagnostic yield.

The net effect is a list that better reflects the differential you will actually see: toxic alcohols, sepsis- or drug-related lactate, D-lactate in short-gut patients, 5-oxoproline in polypharmacy, and the chronic organ-failure triad of renal disease and ketoacidosis. GOLD MARK is taught alongside rather than instead of MUDPILES — knowing both gives you a robust, redundancy-checked recall.

Key takeaways

• GOLD MARK = Glycols, 5-Oxoproline, L-Lactate, D-Lactate, Methanol, Aspirin, Renal failure, Ketoacidosis.
• It modernizes MUDPILES by adding D-lactate and 5-oxoproline and dropping cyanide, formaldehyde, and paraldehyde.
• It foregrounds toxic alcohols (the most time-critical HAGMA cause) by grouping the glycols under one letter.
• Confirm the gap with the anion gap calculator and pair with the osmolar gap when a glycol or methanol ingestion is on the table.

MUDPILES vs GOLD MARK — what changed and why

MUDPILES and GOLD MARK cover the same physiological territory — endogenous organic acids, inorganic acid retention, and exogenous toxins — but they were codified forty years apart in very different clinical eras. MUDPILES took shape in the 1970s, when paraldehyde, cyanide, and formaldehyde ingestions were still realistic bedside possibilities and D-lactate had not yet been described as a clinical entity. GOLD MARK was proposed in 2008 to reflect what modern ICU and emergency practice actually sees: toxic alcohols remain common and time-critical, D-lactate is a recognized short-bowel syndrome cause, 5-oxoproline acidosis appears with polypharmacy, and the historical toxins have largely vanished (Mehta AN, Lancet 2008). The result is a list that foregrounds the diagnoses that matter today rather than the ones that filled teaching syllabi a generation ago.