Why this poison is interesting

Someone drinks antifreeze. For the first few hours they look drunk, and then they stop looking drunk. Somewhere between hour eight and hour twenty-four their bicarbonate collapses, and a day after that their kidneys fail. At no point in that sequence is the substance they swallowed doing very much.

The EXTRIP workgroup's systematic review states it flatly: "EG itself has minimal toxicity, but its metabolites are responsible for most of the clinical effects".¹ The pivotal fomepizole trial makes the same point from the other end — among nineteen poisoned patients, "renal injury was independent of the initial plasma ethylene glycol concentration".³ The thing you can measure is not the thing that hurts them.

That produces a clinical shape that catches people out in a very specific way. The patient is at their most reassuring exactly when the damage is being manufactured, because the parent alcohol has worn off and the metabolite has not yet accumulated enough to show. Treating on symptoms means treating after the injury; treating on mechanism means treating a patient who looks fine.

A poison is a drug whose kinetics have escaped its pharmacology.

The toxic principle

There are two toxic species, they arrive at different times, and they injure different organs. Conflating them is the commonest way this poisoning is misunderstood.

Glycolate: The acidaemia. It is the anion that opens the anion gap, and EXTRIP is explicit that complications are predicted by the plasma glycolate concentration and the associated acid–base disorder, not by the ethylene glycol concentration.¹ Established
Calcium oxalate monohydrate: The kidney. Glyoxylate is oxidised to oxalate, which precipitates with calcium as crystals that adhere to and are internalised by proximal tubular cells.^1,4 Inferred
Ethylene glycol itself: A CNS depressant, roughly comparable to ethanol, and essentially nothing else.¹ It also carries the osmolar gap — which means the osmolar gap measures the least dangerous molecule in the patient. Established

Toxicokinetics

Ethylene glycol and glycolate — figures from the EXTRIP systematic review unless stated
Parameter	Therapeutic	In overdose	Why it changes
Absorption	Small, water-soluble; quickly and completely absorbed from the gastrointestinal tract¹	Unchanged. There is no modified-release antifreeze	Nothing about the substance delays absorption, so the clock that matters starts at ingestion rather than at some later peak. What is delayed is metabolism, and that delay is the entire latent period.
Protein binding	Negligible for ethylene glycol; 0% for glycolate¹	Unchanged	Both toxin and metabolite circulate entirely free, which is why plasma concentrations mean what they appear to mean and why an extracorporeal circuit can remove them efficiently.
Volume of distribution	0.5–0.8 L/kg (glycolate 0.5–0.6)¹	Unchanged — distributes into total body water¹	Small and unchanging. Every physicochemical property points the same way: this is a dialysable poison, and so is its principal metabolite.
Half-life	2–5 h with no antidote and normal kidneys (glycolate 2–7 h)¹	12–18 h on fomepizole; 40–80 h on fomepizole with kidney injury.¹ Measured at 19.7 ± 1.3 h on fomepizole monotherapy in the trial cohort, versus <8.6 ± 1.1 h with no antidote²	The antidote deliberately prolongs the poison's half-life, and that is the therapy rather than a side effect of it. Blocking alcohol dehydrogenase converts a rapidly metabolised toxin into a slowly excreted inert one. You are not clearing ethylene glycol faster; you are making sure it leaves as ethylene glycol.
Elimination route	Two-thirds oxidised by hepatic alcohol dehydrogenase; one-third excreted unchanged in urine.¹ Total body clearance ~100 mL/min, a quarter of it renal¹	With ADH blocked, renal excretion becomes essentially the only route;^1,2 fractional renal excretion 25.5 ± 9.4%²	This row decides who needs dialysis. On fomepizole, elimination is proportional to creatinine clearance² — so renal function, not the ethylene glycol concentration, determines whether the antidote alone can finish the job.
Order of kinetics	First order, though a biphasic profile is described¹	First order during fomepizole monotherapy, and unaffected by the presence of ethanol²	Ethylene glycol is not a saturation poison. Nothing here becomes zero-order, no binding site fills up, and no apparent volume changes. It is purely a pathway-diversion poison, which is why a single enzyme block is such a complete answer to it.
Dialysability	—	Ethylene glycol: dialysable, level of evidence B. Glycolate: dialysable, level of evidence C.¹ Haemodialysis clearance approximates plasma flow and can exceed 200 mL/min — at least an 800% increase over endogenous clearance with adequate ADH blockade¹	Small, unbound, water-soluble, low Vd — the textbook profile. Note that dialysis removes the parent and the metabolite, which matters, because by the time most patients are sick it is the metabolite that is doing the harm.

Metabolism and the metabolites

Four enzymatic steps separate a swallow of coolant from renal failure. Only the first of them can be blocked, which is why the whole of management is a race to block it.

Ethylene glycol — the metabolic cascade, and where the antidote acts

Ethylene glycolMW 62 Da. Minimal intrinsic toxicity beyond CNS depression¹
Alcohol dehydrogenase — THE STEP FOMEPIZOLE AND ETHANOL BLOCKTwo-thirds of an absorbed dose takes this route; the other third is excreted unchanged in urine¹
GlycolaldehydeTransient — rapidly converted onwards¹
Aldehyde dehydrogenaseFast, and not a useful therapeutic target¹
GlycolateMW 76 Da. The acidaemia. The metabolite whose concentration predicts complications¹
Glycolate oxidase — the RATE-LIMITING step¹Glycolate accumulates precisely because this is the bottleneck: it is made faster than it is consumed
Glyoxylate
Oxidation, then precipitation with calciumCalcium oxalate monohydrateCrystals adhere to tubular cell membranes and are then internalised^1,4
Transamination and other routesGlycine, α-hydroxy-β-ketoadipateNon-toxic products¹ — the escape routes that pyridoxine and thiamine are given to favour

What changes the answer

Co-ingested ethanol is protective. Ethanol competes for alcohol dehydrogenase, and EXTRIP lists it explicitly as a modulator of toxicity because it decreases ethylene glycol metabolism.¹ A patient who drank vodka with the antifreeze has, accidentally, started their own antidote. Established
Fomepizole has a stronger affinity for ADH than ethanol does, which is why the elimination half-life is longer on fomepizole than on ethanol (12–18 h versus 8.5–14 h without kidney injury).¹ A longer half-life here means a better block. Established
Kidney impairment changes everything downstream of the block. With ADH inhibited and kidneys working, the half-life is 12–18 h; with ADH inhibited and kidneys impaired it is 40–80 h.¹ The antidote closes one exit, so the remaining exit has to work. Established
Delay is the dominant prognostic variable. EXTRIP found that ethylene glycol dose predicts outcome only if there is a delay to treatment,¹ and that a delay of 6–12 hours between ingestion and treatment is associated with increased complications in several series (though not in all).¹ Inferred

Elimination and accumulation

The unusual feature of ethylene glycol elimination is that treatment reverses which route matters. Untreated, two-thirds of the dose leaves down a metabolic path that generates the poison; treated, essentially all of it has to leave through the kidney unchanged.^1,2 The therapeutic act is a redirection, not an acceleration.

Renal elimination is proportional to creatinine clearance. In the fomepizole cohort, fractional renal excretion was 25.5 ± 9.4%, and all patients with normal serum creatinine at the start of treatment eliminated rapidly (half-life 16.8 ± 0.8 h).² Established
Renal excretion and haemodialysis were the only significant routes of elimination as long as fomepizole concentrations were maintained well above 10 µmol/L.² The block is close to complete when it is adequately dosed. Established
There is no ion trapping, no enterohepatic recirculation and no rise in free fraction to manage — the accumulation problem here is entirely the metabolite piling up behind glycolate oxidase, not the parent compound hiding anywhere.

The EXTRIP position on dialysis

Ghannoum and colleagues reviewed 226 articles and clinical data on 446 patients, with overall mortality 18.7%.¹ The finding that shapes the recommendations is a subgroup one: in patients with a glycolate concentration ≤12 mmol/L (or anion gap ≤28 mmol/L), mortality was 3.6% — and in that subgroup, outcomes in patients receiving extracorporeal treatment were no better than in those who did not.¹

The recommendations follow, with very low quality of evidence for all of them:¹

Suggest ECTR if fomepizole is used and ethylene glycol >50 mmol/L (310 mg/dL) or osmol gap >50.¹
Recommend ECTR if ethanol is used and ethylene glycol >50 mmol/L or osmol gap >50 — a stronger recommendation than for fomepizole, for the same numbers; and suggest it on ethanol at 20–50 mmol/L (124–310 mg/dL) or osmol gap 20–50.¹
Recommend ECTR if no antidote is available and ethylene glycol is >10 mmol/L (62 mg/dL) or osmol gap >10.¹ Note how far this threshold falls once nothing is blocking alcohol dehydrogenase — it is five-fold below the figure that applies on fomepizole, and it is the arm most easily overlooked.
Recommend ECTR if glycolate >12 mmol/L or anion gap >27 mmol/L; suggest it if glycolate 8–12 mmol/L or anion gap 23–27 mmol/L.¹ EXTRIP calculates the anion gap here with potassium — Na⁺ + K⁺ − Cl⁻ − HCO₃⁻ — which is not the formula used in its methanol recommendations, so the two sets of thresholds are not on the same scale.
Recommend ECTR if there are severe clinical features — coma, seizures or acute kidney injury.¹
Intermittent haemodialysis is preferred; CKRT if it is not available.¹
Stop once the anion gap is <18 mmol/L, or (suggested) once ethylene glycol is <4 mmol/L (25 mg/dL), or (suggested) once acid–base abnormalities are corrected. Antidote dosing must be adjusted during ECTR — fomepizole and ethanol are themselves dialysed out.¹

Target organs — and why those

Kidney — proximal tubule

TargetCalcium oxalate monohydrate crystals

Why hereOxalate is generated in the liver, filtered, and then concentrated along the tubule as water is reabsorbed — so the proximal tubule is where the calcium oxalate solubility product is exceeded first. What follows is not simply obstruction: crystals adhere to the tubular cell membrane and are then internalised, and McMartin's review argues that in human proximal tubule cell culture it is the crystals specifically — not the oxalate ion, not glycolaldehyde, not glyoxylate — that produce necrotic cell death at toxicologically relevant concentrations, by disrupting membranes, raising reactive oxygen species and causing mitochondrial dysfunction.⁴ Inferred

At the bedsideAcute kidney injury occurs in 30–70% of reported cases¹ and is closely correlated with the other outcomes. Hypocalcaemia and QT prolongation can accompany it — the calcium is being consumed to build the crystals. Inferred

Central nervous system — twice, by two different mechanisms

TargetEthylene glycol itself early; oxalate deposition and severe acidaemia late

Why hereThe early picture is straightforward CNS depression by a small alcohol, indistinguishable from drunkenness apart from the absent smell. The late picture — coma, cerebral oedema, seizures — arrives with the acidaemia, and the cranial nerve palsies, radiculopathy and other neuropathies may appear several days after ingestion, despite treatment.¹ Two mechanisms at two times is why the neurology has two peaks and why the second one is not prevented by having treated the first. Inferred

At the bedsideBrainstem and basal ganglia injury are reported but rare.¹ A late cranial neuropathy in a treated patient is not treatment failure in the usual sense — the crystals were deposited before the antidote arrived.

Circulation and lungs — stage 2

TargetSystemic glycolate acidaemia

Why hereGlycolate is a small unbound organic acid distributing through total body water,¹ so its effect is systemic rather than organ-specific: a severe high-anion-gap metabolic acidosis producing Kussmaul respiration, tachycardia, hypertension or hypotension, and acute respiratory distress. EXTRIP states that complications are predicted by the plasma glycolate concentration and the associated acid–base disorder.¹ Established

At the bedsideThis is the stage at which multi-organ failure and death occur, and it precedes the renal stage. A patient can die of the acidosis before the crystals have had time to fail their kidneys.

Timeline of effects

Ethylene glycol — the untreated course, and what is happening underneath it

Time

What you seeWhat is happening

0–3 hStage 1 — inebriation
What you seeLooks drunk: ataxia, slurred speech, nystagmus, vomiting. No smell of alcohol on the breath, which is the only external clue. In a smaller ingestion, or one taken with alcohol, there may be nothing at all.
What is happeningEthylene glycol is itself the CNS depressant.¹ Alcohol dehydrogenase is already converting it to glycolaldehyde and on to glycolate, but nothing toxic has yet accumulated. The osmolar gap is at its widest now and the anion gap is normal — the mirror image of where they will be in six hours.
3–12 hLatent — acidaemia from ~3–6 h
What you seeThe inebriation wears off. The patient often looks better than they did on arrival, and may be alert, oriented and asking to leave. There is no sign, no symptom and no finding on examination. This is the interval in which people are discharged.
What is happeningGlycolate accumulates behind the rate-limiting glycolate oxidase step.¹ Bicarbonate falls, the anion gap opens, and the osmolar gap closes as parent alcohol is converted to metabolite. Metabolic acidaemia appears after a latent period of roughly 3–6 hours.¹ Nothing has been injured yet — and everything that will do the injuring has already been made.
12–24 hStage 2 — cardiopulmonary
What you seeKussmaul respiration, tachycardia, hypertension or hypotension, acute respiratory distress. Severe high-anion-gap metabolic acidosis. Progressive neurotoxicity: coma, cerebral oedema, seizures. Multi-organ failure and death can occur at this stage.¹
What is happeningGlycolate acidaemia, systemic because glycolate is unbound and distributes through total body water. Serum lactate may read high — sometimes genuinely, sometimes because glycolate and glyoxylic acid cross-react with the lactate oxidase in blood gas analysers.⁶
24–72 hStage 3 — renal
What you seeOliguria, flank pain, rising creatinine. Acute kidney injury in 30–70% of reported cases.¹ Crystalluria may be present but its absence proves nothing.
What is happeningCalcium oxalate monohydrate crystals have adhered to and been internalised by proximal tubular cells; membrane disruption, reactive oxygen species and mitochondrial dysfunction produce tubular necrosis.⁴ The severity of renal damage correlates with the total crystal accumulation in kidney tissue, not with the parent alcohol concentration.^3,4
Days to weeksLate
What you seeCranial nerve palsies, radiculopathy and other neuropathies may appear several days after ingestion, despite treatment.¹ Renal recovery is usual but neither universal nor quick.
What is happeningInjury from crystal deposition that occurred during the acute phase, becoming clinically apparent only as the affected tissue fails. Nothing given now alters it — which is the strongest argument for treating early that this poisoning offers.

What the mechanism predicts at the bedside

Why you treat before there are symptoms

The pivotal fomepizole study is unusually clean on this point. Nineteen patients; fifteen were acidotic on arrival (mean bicarbonate 12.9 mmol/L). Nine deteriorated renally — and every one of those nine already had a raised creatinine and a markedly elevated glycolate (≥12.9 mmol/L) at enrolment. None of the ten with a normal creatinine at enrolment developed renal injury, and all ten had glycolate at or below 10.1 mmol/L.³ The conclusion the authors drew is the whole argument for early treatment: fomepizole given early "prevents renal injury by inhibiting the formation of toxic metabolites".³ Established

Why the anion gap can stand in for a glycolate level

Glycolate assays are a send-away test almost everywhere in the UK; the anion gap is available in minutes. Because glycolate is the unmeasured anion doing the work, the gap tracks it. The systematic review of monotherapy analysed 207 cases and found that death and progression of acute kidney injury were almost non-existent when the anion gap was below 24 mmol/L, and were mostly seen above 28 mmol/L.⁵ EXTRIP's own dialysis thresholds pair each glycolate cut-point with an anion-gap equivalent for exactly this reason.¹ Established

Why fomepizole alone is often enough

If the poison is the metabolite, and the metabolite is no longer being made, then the only remaining task is to excrete an inert alcohol — which a working kidney does. That prediction has been tested: reviewing 231 cases of fomepizole monotherapy without any extracorporeal treatment, Beaulieu and colleagues concluded that in patients with minimal metabolic acidaemia (anion gap <28 mmol/L), fomepizole monotherapy without extracorporeal treatment is safe and effective regardless of the ethylene glycol concentration.⁵ Ethylene glycol dose and concentration predicted failure of ethanol monotherapy but not of fomepizole.⁵ Inferred

Sivilotti and colleagues reached the same place from the kinetics twenty years earlier, and stated the consequence explicitly: "An absolute EG concentration above 50 mg/dL should no longer be used as an independent criterion for hemodialysis in patients treated with fomepizole."² That is a mechanism argument changing a threshold, which is the reason this site exists.

Why a normal osmolar gap does not exclude the diagnosis

The osmolar gap measures unmetabolised ethylene glycol, so it decays as the poisoning progresses. A patient presenting at eighteen hours may have converted most of their dose already: normal osmolar gap, wide anion gap, and a kidney about to fail. EXTRIP notes that reported toxicity at ethylene glycol concentrations below 3.2 mmol/L occurs exclusively in patients who had already metabolised the alcohol by the time of testing.¹ Established

Why the lactate may be a lie — and may not be

Glycolate and glyoxylic acid are structurally close enough to lactate to cross-react with the lactate oxidase enzyme used by blood gas analysers. In a multi-centre comparison across 20 analysers from nine manufacturers, samples spiked with glycolate or glyoxylic acid produced falsely elevated L-lactate with all blood gas methods and with the majority of general chemistry methods using lactate oxidase, while ethylene glycol itself, glyoxal and oxalate did not interfere.⁶ Established

Two practical consequences, and the second is the one usually missed. The difference between a lactate measured on a gas analyser and one measured on a central chemistry platform — the "lactate gap" — can itself point to the diagnosis.⁷ But lactate can also be genuinely elevated in this poisoning, and treating every high lactate as artefact is the mirror-image error.⁸ Confirm on a second method rather than assuming either way.

The Wood's lamp

The teaching that urine will fluoresce under a Wood's lamp because antifreeze contains sodium fluorescein is traditional teaching. Traditional teaching When 60 physicians rated 150 urine specimens from non-poisoned children, group 1 reported fluorescence in 80.7% of specimens and group 2 in 69.3%; interrater agreement was poor (κ = 0.25); and by fluorometry the prevalence of urine fluorescence in these unpoisoned children was 100% (95% CI 98.1–100%). The authors concluded it is a poor screening tool.⁹ Normal urine fluoresces. The test cannot do what it is taught to do.

The antidote, from the poison's side

Fomepizole

A competitive inhibitor of alcohol dehydrogenase, and therefore an answer aimed at the first step of the cascade rather than at any of its products. Everything about the poisoning follows from that placement:

It prevents rather than reverses. Glycolate already made is not removed by blocking the enzyme, and crystals already deposited are not dissolved by it. Its entire benefit is in metabolite not made, which is why time to administration dominates outcome.³ Established
It lengthens the parent compound's half-life to 12–18 h, or 40–80 h with kidney injury.¹ A longer half-life is the evidence that it is working.
It has a stronger affinity for ADH than ethanol,¹ which is why its block is more reliable and why it needs no concentration monitoring.
It is itself dialysed, so dosing must be adjusted during extracorporeal treatment.¹ Established

Ethanol

The same idea by competition rather than inhibition: give alcohol dehydrogenase a substrate it prefers. It works, and where fomepizole is unavailable it is a real answer. Its weaknesses are all consequences of being a substrate rather than an inhibitor — a therapeutic concentration has to be reached and then held, it is itself a CNS depressant and hypoglycaemic agent in the doses required, and the systematic review of monotherapy found failures with ethanol even at minimal acidaemia, plausibly reflecting transient subtherapeutic concentrations.⁵ EXTRIP's stronger dialysis recommendation on ethanol than on fomepizole for identical numbers encodes exactly this.¹

Pyridoxine and thiamine

Given on the rationale that they favour the non-toxic exits from glyoxylate — transamination to glycine, and conversion to α-hydroxy-β-ketoadipate — and so divert flux away from oxalate.¹ That is a coherent biochemical argument and both are cheap and harmless. The step has not been shown to change outcomes in humans, and it should be described as a plausible adjunct rather than as an established antidote. Inferred

Critical appraisal

There is no defensible human toxic dose. EXTRIP states plainly that "a threshold dose for toxicity is poorly defined in humans": de-icing workers systemically exposed to an estimated 27 mg/kg had no adverse effects, self-experiments with 10–30 mL of pure ethylene glycol caused no harm, and in one cohort of 86 unintentional ingestions of under 100 mL every patient survived — though most were treated within three hours.¹ Figures for a minimum lethal dose circulate widely; EXTRIP's own review notes that toxicity and death have occurred below the commonly quoted figure, and that dose predicts outcome only when there is a delay to treatment.¹ A number that is both unreliable and only conditionally relevant is not worth printing, and is not printed here.
A concentration threshold for toxicity is similarly unknown. The 20 mg/dL (3.2 mmol/L) figure used to trigger treatment is a treatment threshold, not a toxicity threshold — EXTRIP describes some sources quoting it as a risk level and notes that no toxicity occurred in seven untreated patients below 4.8 mmol/L, while stating that because ethylene glycol itself causes little toxicity, the concentration is poorly predictive of mortality.¹ The threshold is doing a different job from the one its units suggest.
The calcium oxalate crystal mechanism is strong but not demonstrated in humans. Inferred McMartin's review argues that recent studies show "definitively" that crystal accumulation produces the tubular necrosis, on the basis of dose–response correlation in ethylene glycol-dosed rats and necrotic death produced by crystals — but not by the oxalate ion, glycolaldehyde or glyoxylate — in cultured human proximal tubule cells.⁴ That is a model reproducing the human lesion rather than a demonstration in humans, and the same review opens by acknowledging that "the mechanism has not been established". The older teaching that the aldehyde metabolites are directly nephrotoxic is what this displaces.
Every EXTRIP recommendation here rests on very low quality evidence, stated as such by the workgroup.¹ The thresholds are the product of a structured Delphi process over 226 articles and 446 patients, not of a trial. They are the best available and should be used; they should not be quoted as though they were measured.
The evidence that fomepizole monotherapy suffices is retrospective and needs prospective validation — the authors say so.⁵ It is assembled from case reports and series, with all the publication bias that implies, and the anion-gap analysis rests on 207 cases. The conclusion is well-argued and consistent with the kinetics, and it is still a systematic review of case reports.
"Falsely elevated lactate" is a real interference that is now over-taught. Inferred The laboratory work is solid — glycolate and glyoxylic acid cross-react with lactate oxidase across most analysers⁶ — but Meng and colleagues reported two cases in which only one showed the artefact, and concluded that a true increase in lactate can also occur in ethylene glycol poisoning.⁸ The safe reading is that a high lactate here requires confirmation on a second method, not dismissal.
The osmolar gap is treated as a screening test far more confidently than it deserves. Its behaviour over time is a mechanism problem, not a laboratory one: it measures the parent alcohol and therefore decays as the poisoning matures.¹ Its use as a rule-out is the single most predictable way to miss this diagnosis late.

References

1
Ghannoum M, Gosselin S, Hoffman RS, et al., on behalf of the EXTRIP workgroup. Extracorporeal treatment for ethylene glycol poisoning: systematic review and recommendations from the EXTRIP workgroup. Crit Care 2023;27:56. doi:10.1186/s13054-022-04227-2. PMC9921105 Open access. Source of the toxicokinetic table (molecular weights, protein binding, volumes of distribution and every half-life figure), the metabolic pathway including glycolate oxidase as the rate-limiting step, the 3–6 h latent period, the 30–70% AKI incidence, the late cranial neuropathies, the 18.7% overall and 3.6% subgroup mortality, all dialysability gradings and every ECTR recommendation quoted above, and the statements on threshold dose and concentration. Verified 31 Aug 2026 from the full text.
2
Sivilotti MLA, Burns MJ, McMartin KE, Brent J, for the Methylpyrazole for Toxic Alcohols Study Group. Toxicokinetics of ethylene glycol during fomepizole therapy: implications for management. Ann Emerg Med 2000;36(2):114–25. PubMed 10918102 Source of the 19.7 ± 1.3 h and <8.6 ± 1.1 h half-lives, the 25.5 ± 9.4% fractional renal excretion, the 10 µmol/L fomepizole concentration point, and the quoted conclusion that an absolute concentration above 50 mg/dL should no longer be an independent haemodialysis criterion on fomepizole. Verified 31 Aug 2026.
3
Brent J, McMartin K, Phillips S, Burkhart KK, Donovan JW, Wells M, Kulig K, for the Methylpyrazole for Toxic Alcohols Study Group. Fomepizole for the treatment of ethylene glycol poisoning. N Engl J Med 1999;340(11):832–8. PubMed 10080845 Source of the ≥20 mg/dL (3.2 mmol/L) enrolment threshold, the mean bicarbonate of 12.9 mmol/L, the 9-versus-10 patient renal outcome split with its glycolate figures, and the quoted statement that renal injury was independent of the initial plasma ethylene glycol concentration. Verified 31 Aug 2026.
4
McMartin K. Are calcium oxalate crystals involved in the mechanism of acute renal failure in ethylene glycol poisoning? Clin Toxicol (Phila) 2009;47(9):859–69. PubMed 19852621 Source of the calcium oxalate monohydrate crystal mechanism — adherence, internalisation, membrane disruption, reactive oxygen species and mitochondrial dysfunction — and of the finding that crystals rather than the oxalate ion, glycolaldehyde or glyoxylate produce necrotic death in human proximal tubule cells. Rat and cell-culture evidence; not demonstrated directly in humans. Verified 31 Aug 2026.
5
Beaulieu J, Roberts DM, Gosselin S, et al. Treating ethylene glycol poisoning with alcohol dehydrogenase inhibition, but without extracorporeal treatments: a systematic review. Clin Toxicol (Phila) 2022;60(7):784–97. PubMed 35311442 Source of the 180 ethanol and 231 fomepizole monotherapy cases, the anion-gap analysis (207 cases; death and AKI progression almost non-existent below 24 mmol/L and mostly above 28 mmol/L), and the conclusion on fomepizole monotherapy safety below an anion gap of 28 mmol/L. The authors state the results require prospective validation. Verified 31 Aug 2026.
6
Tintu A, Rouwet E, Russcher H. Interference of ethylene glycol with (L)-lactate measurement is assay-dependent. Ann Clin Biochem 2013;50(Pt 1):70–2. PubMed 23129723 Serum spiked at 12.5 mmol/L and measured on 20 analysers from nine manufacturers across 31 hospitals: glycolate and glyoxylic acid falsely elevated L-lactate with all blood gas methods and most lactate-oxidase chemistry methods; ethylene glycol, glyoxal and oxalate did not interfere. Verified 31 Aug 2026.
7
Verelst S, Vermeersch P, Desmet K. Ethylene glycol poisoning presenting with a falsely elevated lactate level. Clin Toxicol (Phila) 2009;47(3):236–8. PubMed 19016054 Source of the "lactate gap" concept — comparing two technologies of which only one is sensitive to glycolate. Verified 31 Aug 2026.
8
Meng QH, Adeli K, Zello GA, Porter WH, Krahn J. Elevated lactate in ethylene glycol poisoning: true or false? Clin Chim Acta 2010;411(7–8):601–4. PubMed 20096388 Two cases: artefact in one, a genuine lactate rise in the other. The source for not dismissing a raised lactate as interference. Verified 31 Aug 2026.
9
Parsa T, Cunningham SJ, Wall SP, Almo SC, Crain EF. The usefulness of urine fluorescence for suspected antifreeze ingestion in children. Am J Emerg Med 2005;23(6):787–92. PubMed 16182989 Source of all the Wood's lamp figures quoted above, including the 100% (95% CI 98.1–100%) prevalence of urine fluorescence by fluorometry in non-poisoned children. This is the citation for the doubt that justifies the traditional-teaching badge. Verified 31 Aug 2026.
10
TOXBASE — ethylene glycol; fomepizole. National Poisons Information Service. toxbase.org (NHS login required. NPIS: 0344 892 0111. The authoritative UK source for treatment thresholds, antidote choice and dosing, and dialysis criteria. Login-gated, so not quoted here.)

Ethylene glycol

At a glance