D-Dimer and Snake Venom: Dr. Ardis on Blood Clots After Vaccination

Table of Contents

1. What Dr. Ardis Says, in His Own Words
2. Dr. Hoffe’s D-Dimer Tests
3. The Medscape Article and Its Five Bullets
4. Why Dr. Ardis Sets Aside the Other Four Bullets
5. From the Fifth Bullet to Karikó and Weissman
6. A Plain Primer: What D-Dimer Is
7. What Else Raises D-Dimer
8. Warfarin, Heparin and Coumadin
9. What Snake Venom Does to D-Dimer
10. Dr. Ardis’s Sources
11. Key Research Papers
12. Connections
13. Featured Videos

1. What Dr. Ardis Says, in His Own Words

Dr. Bryan Ardis, a chiropractor and podcaster, has told the D-dimer part of his snake-venom argument more than once. Two tellings are quoted here. The first is from a May 2025 podcast, Culture Apothecary with Alex Clark, in the chapter titled “What is a D-Dimer Test?” (34:32–36:17):

I decided to go find out, well, what is a D-dimer even tell a person about those blood clots? So I looked it up on medscape.com. You can look at the article now. These are the five things they tell you to look for. … The Medscape medical journals online, the textbooks say go look for snake venom poisoning. … The 5th bullet point is the only thing that would explain Charles Hoff[e] MD’s patients who got the COVID-19 vaccines having elevated D dimers because none of them were on those three drugs that break up blood clots, warfarin, heparin and Coumadin.

The second is from the 2023 film Watch the Water 2, where he walks through the same steps at more length. It begins with Dr. Hoffe:

But what did Charles Hoffe MD out of British Columbia Canada say two summers ago? He said I ran the mRNA injected patients blood … Every mRNA injected patient for Covid, 60% of all of them had elevated D-dimers. … I looked it up. … Medscape.com in 2019….updated it again in 2022, has one article on how to interpret elevated D-dimers. And there is five bullet points.

Put together, his chain runs in four steps:

1. Dr. Charles Hoffe, a physician in British Columbia, reported raised D-dimer results in patients after mRNA COVID-19 vaccination — “60% of all of them,” in Dr. Ardis’s telling (section 2).
2. Dr. Ardis looked up what a raised D-dimer is meant to tell a doctor and found one Medscape article with five bullet points (section 3).
3. The first four, he says, “describe different types of blood clots”; the fifth reads “Snake venom poisoning,” which he sees as the only one that could explain the patients’ results (section 4).
4. So he asked who created the mRNA shots, found Katalin Karikó and Drew Weissman, and points to “snake venom phosphodiesterase” in their research papers (section 5).

The sections below take those steps in turn.

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2. Dr. Hoffe’s D-Dimer Tests

Dr. Charles Hoffe is a physician in Lytton, British Columbia. In interviews in mid-2021 he said he had run D-dimer tests on patients four to seven days after mRNA COVID-19 vaccination and found the result raised in 62% of them.

Dr. Ardis gives the figure as 60%: “Every mRNA injected patient for Covid, 60% of all of them had elevated D-dimers.” He also passes on what he took to be Dr. Hoffe’s message to other doctors. Dr. Hoffe, he says, “said everyone needs to be running this test on Covid vaccine injected patients….this elevated D-dimer test tells you that there is clotting going on everywhere in the body.”

The test was new to Dr. Ardis. “I was like elevated D-dimers? I don’t even know what that is,” he says. He wanted to know what doctors and laboratory staff are trained to look for when a result comes back raised, so he searched the question “How are elevated D-dimers interpreted?” — “So I went online and looked it up,” in his words. That search led him to the Medscape article in the next section.

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3. The Medscape Article and Its Five Bullets

Medscape is an online medical reference written for doctors. Its entry “D-Dimer”, in the Laboratory Medicine section, is the article Dr. Ardis describes as Medscape’s “one article on how to interpret elevated D-dimers.” The archived copy quoted on this page is marked “Updated: Feb 22, 2022.”

Under the heading “Interpretation”, the article lists five situations where a raised result is useful — in its own words, where the test provides “clinical utility”. Verbatim (numbered here so the bullets can be referred to; the original uses plain bullets):

Elevated D-dimer levels reflect ongoing activation of the hemostatic and thrombolytic system, providing clinical utility in the following:

1. Evaluation of thrombus formation
2. Ruling out DVT (discussed further below)
3. Monitoring anticoagulative treatment (a decreasing value indicates effective treatment)
4. Disseminated intravascular coagulation (DIC)
5. Snake venom poisoning

The fifth bullet reads “Snake venom poisoning,” exactly as Dr. Ardis says. The list is followed by a paragraph on what else raises D-dimer; that paragraph is quoted in full in section 7.

In plain words, the five bullets are:

• Evaluation of thrombus formation — a thrombus is a blood clot inside a vessel.
• Ruling out DVT — deep-vein thrombosis, a clot in a deep vein, usually in the leg.
• Monitoring anticoagulative treatment — following patients on blood-thinning drugs (section 8).
• DIC — disseminated intravascular coagulation, a condition in which clotting is switched on throughout the bloodstream.
• Snake venom poisoning — snakebite (section 9).

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4. Why Dr. Ardis Sets Aside the Other Four Bullets

Of the five bullets, Dr. Ardis treats only the last as a cause. In Watch the Water 2 he explains why:

The first four describe different types of blood clots in the body….Blood clot, blood clot….go look for this blood clot, go look for this blood clot in the brain, the lungs, in the legs…that’s what they describe. If you see elevated D-dimers, go look for blood clots. … of the five bullet points that they tell all medical doctors to go look for when they see elevated D-dimers, there is only one listed that could cause the elevated D-dimers….blood clot to show up. And it says “snake venom poisoning!”

In the 2025 podcast he adds a second reason, about medication. The fifth bullet, he says, is “the only thing that would explain Charles Hoff[e] MD’s patients who got the COVID-19 vaccines having elevated D dimers because none of them were on those three drugs that break up blood clots, warfarin, heparin and Coumadin.” The third bullet is the one about drug treatment: “Monitoring anticoagulative treatment.” Section 8 sets out what those drugs are.

He reads the fifth bullet as an instruction to doctors. In the film he puts it this way: “you, M.Ds, when you see elevated D-dimers, go look for snake venom poisoning.” In the podcast: “the textbooks say go look for snake venom poisoning.”

The two venom proteins he says to test for

Elsewhere in the same film, Dr. Ardis names two snake-venom proteins that he says should be tested for when the result is raised: “all you have to do is to go test for Ecarin and Textilinin if you see elevated D-Dimers.” In his description, ecarin comes “from the saw-scaled viper snake” and “initiates the rapid blood clotting,” while textilinin “blocks the body’s ability to break down blood clots” and, he says, resists heparin and warfarin.

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5. From the Fifth Bullet to Karikó and Weissman

With snake venom on Medscape’s list, Dr. Ardis took his next step. In Watch the Water 2:

If snake venom could be causing blood clotting that Charles Hoffe is saying is causing elevated D-dimers in his mRNA injected patients, I want to know, did the researchers who created the Covid19 mRNA shots….all I did was find out who were they. Its Drew Wiseman [Weissman] and Katalin Karikó at the University of Pennsylvania.

In the 2025 podcast, at 29:03, he describes what he says he found in their work:

Their names are Katalin Karikó and Drew Weissman. And when you go look at their research studies, they were funded by the NIH starting in 2009 to develop these COVID-19 mRNA vaccines. Strange. And in every one of those research studies, they state snake venom phosphodiesterase, snake venom…

In the film he calls the papers the shots’ “recipes”:

every single one of their … studies says that in order to cleave…cut RNA or DNA, they use snake venom phosphodiesterase … to cleave the RNA or DNA to insert the mRNA for our gene therapy. … when I say I am worried that there is snake venom in the shots….why don’t you go look at the recipes of the researchers who created the shots. Stew, the … words “snake venom” is in the paper.

His show also posted a clip whose title points to two years: “Covid Vax Synthetic Snake Venom Research Funded by NIH Grant to mRNA Scientists Katalin Kariko and Drew Weissman 2008 & 2011.” Two Karikó–Weissman papers from those years, a 2008 paper in Molecular Therapy and a 2011 paper in Nucleic Acids Research, are listed under Key Research Papers.

Here his D-dimer chain hands over to the papers themselves. The Snake Venom Phosphodiesterase in the Karikó–Weissman Papers page sets the papers’ exact sentences beside his words, and The NIH Grants Behind the Karikó–Weissman Research lists the grants he refers to. The wider venom argument he makes in the first Watch the Water film is on the Snake Venom Hypothesis page.

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6. A Plain Primer: What D-Dimer Is

This section and the three after it are a plain reference primer on the test itself, drawn from the Medscape article Dr. Ardis cites and from the medical literature.

A blood clot is built in stages. The raw material is fibrinogen, a clotting protein carried in the blood: a long molecule with a D region at each end. When a blood vessel is injured, the enzyme thrombin turns fibrinogen into fibrin, and the fibrin strands line up end to end into a mesh. Then factor XIII stitches the strands together, welding the D regions of neighbouring strands with strong cross-links so that the mesh holds. Medscape’s one-line definition names that step: “D-dimer is the degradation product of crosslinked (by factor XIII) fibrin.”

No clot is meant to stay forever. As the vessel heals, plasmin, the body’s clot-dissolving enzyme, cuts the stitched mesh apart. Picture a knotted net being cut up: the knots come away still tied. Those knotted pieces — pieces in which two D regions are still stitched together — are D-dimer fragments, “dimer” meaning a pair. They pass into the bloodstream, where they are measured in a blood test. A 2009 review in the journal Blood by Adam, Key and Greenberg describes D-dimer as “formed by the sequential action of 3 enzymes: thrombin, factor XIIIa, and plasmin” (factor XIIIa is factor XIII in its switched-on form).

A little fibrin is always being made and broken down, so healthy people carry a small amount of D-dimer; in Medscape’s words, “healthy individuals have a minimal D-dimer level.” A raised level reflects ongoing clot-making and clot-breaking — Medscape’s phrase is “ongoing activation of the hemostatic and thrombolytic system.”

The diagram below follows how D-dimer is made, from a clot’s building blocks to the fragments a blood test measures, with Medscape’s five bullets beside it.

Read the left column from top to bottom: D-dimer appears only after a clot has been built, stitched by factor XIII and cut by plasmin. The right column is Medscape’s list — its five bullets, with the fifth marked as the bullet Dr. Ardis points to, and the other settings in which it says D-dimer runs high. The drawing is simplified and not to scale.

What the test is used for

The test’s main job is ruling a clot out. Medscape: “The principal utility of measuring D-dimer is the high NPV of the test in the diagnosis of deep venous thrombosis (DVT) in an appropriate clinical setting.” NPV, the negative predictive value, is how far a normal result can be trusted. When a doctor already judges a clot unlikely, a normal D-dimer makes a deep-vein thrombosis or a pulmonary embolism (a clot lodged in the lungs) very unlikely, and can spare the person a scan. Adam’s review names the same main use: “most notably for the exclusion of VTE” — venous thromboembolism, the umbrella term for both.

Cutoffs vary by laboratory, and with age

There is no single normal value. Medscape gives a reference concentration below 250 ng/mL, and adds that the cutoff “is ideally established by the performing laboratory,” while a cutoff taken from the literature has to come from “the same methodology, preferably from the same manufacturer.” A result is therefore read against the range printed by the laboratory that ran it.

Age matters too. The ADJUST-PE study, a prospective study of 3,346 emergency-department patients with a suspected pulmonary embolism at 19 hospitals in Belgium, France, the Netherlands and Switzerland (Righini 2014), set its conventional cutoff at 500 µg/L (the same as 500 ng/mL) and tested an age-adjusted cutoff of age × 10 µg/L for anyone aged 50 or older — 700 µg/L for a 70-year-old, for example. Among the 673 patients aged 75 or older whose clot was not judged highly likely, the age-adjusted cutoff raised the share in whom a clot could be ruled out from 6.4% to 29.7%, without any additional missed clots. Of the untreated patients whose result fell between the two cutoffs, 1 of 331 (0.3%) had a clot in the three months that followed.

The site’s animations show both halves of the story — how blood clots, and how clots dissolve, with D-dimer climbing as plasmin cuts the mesh — and the D-Dimer test page covers the test in depth, alongside the fibrinogen test.

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7. What Else Raises D-Dimer

Medscape follows its five bullets with a second list, on the other settings in which D-dimer runs high. Verbatim:

Additionally, D-dimer levels may be elevated in the setting of pregnancy, inflammation, malignancy, trauma, postsurgical treatment, liver disease (decreased clearance), and heart disease. It is also frequently high in hospitalized patients.

Lipemia, a high triglyceride level, an elevated bilirubin level, an elevated serum rheumatoid factor level, or hemolysis may falsely increase the D-dimer level. … Also keep in mind that the D-dimer level increases naturally with age.

In plain words, Medscape also lists raised levels in:

• pregnancy, inflammation and malignancy (cancer);
• trauma, and the period after surgery (“postsurgical treatment”);
• liver disease, where the liver clears D-dimer from the blood more slowly (“decreased clearance”), and heart disease;
• many people in hospital; and
• age — the level “increases naturally” as people get older, the reason for the age-adjusted cutoff in section 6.

The second paragraph of the quote is about the measurement itself. Lipemia (blood clouded by fat, as with a high triglyceride level), a high bilirubin (the yellow pigment made when old red blood cells are broken down), a high rheumatoid factor (an antibody measured in rheumatoid arthritis) and hemolysis (burst red blood cells) can all “falsely increase” the reading.

Medscape’s background section puts the same point in technical terms: “The D-dimer test has a high sensitivity but low specificity.” High sensitivity means the test seldom misses a clot; low specificity means the level also rises in many other settings, such as those above.

COVID-19 itself

Infection with the virus is one of those settings. Early in the pandemic, two hospital-records studies from Wuhan, China — both retrospective, reading back through patients’ charts — linked raised D-dimer with severe COVID-19:

• Tang and colleagues (2020) reviewed 183 consecutive patients with COVID-19 pneumonia at Tongji Hospital. Overall, 11.5% died. Those who died had significantly higher D-dimer and fibrin degradation products on admission than survivors, and 71.4% of them, against 0.6% of survivors, met the criteria for disseminated intravascular coagulation during their stay.
• Zhang and colleagues (2020) studied 343 patients admitted to Wuhan Asia General Hospital between January 12 and March 15, 2020. A D-dimer of 2.0 µg/mL or more on admission — a fourfold increase, in the authors’ words — predicted death in hospital: 12 of the 67 patients at or above that level died, against 1 of the 267 below it.

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8. Warfarin, Heparin and Coumadin

The three drugs Dr. Ardis names are warfarin, heparin and Coumadin. Coumadin is a brand name of warfarin.

Warfarin and heparin are anticoagulants, the medicines usually called blood thinners. They slow the clotting chain, so that an existing clot stops growing and new clots are less likely to form, while the body’s own plasmin dissolves the clot over time. The two work at different points:

• Warfarin, taken as a tablet, blocks the liver’s recycling of vitamin K, so the clotting factors the liver makes cannot work properly. It is monitored with the PT/INR test; the vitamin K side of the story is on the Vitamin K and Blood Clotting page.
• Heparin, given by injection or drip, boosts antithrombin, the body’s own brake on thrombin. Unfractionated (standard) heparin is monitored with the aPTT test.

Patients on these drugs are the subject of Medscape’s third bullet: “Monitoring anticoagulative treatment (a decreasing value indicates effective treatment).” In someone being treated for a clot, a D-dimer that falls over time is read as a sign that the treatment is working.

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9. What Snake Venom Does to D-Dimer

Medscape’s fifth bullet, “Snake venom poisoning,” refers to snakebite envenoming — venom injected by a bite. The clotting disorder it can cause has its own name in the medical literature: venom-induced consumption coagulopathy, or VICC.

Some snake venoms carry enzymes that switch on the body’s clotting chain directly. A 2010 review by Isbister lists them: VICC “results from activation of the coagulation pathway by snake toxins including thrombin-like enzymes, prothrombin activators, and factor X activators.” Thrombin, prothrombin and factor X are links in the body’s own clotting chain, so these toxins set fibrin-making going inside the bloodstream, and the clotting factors are used up — “consumed,” hence the name. A 2014 review by Maduwage and Isbister puts it this way: the venom’s procoagulant toxins cause “a broad range of factor deficiencies depending on the particular procoagulant toxin in the snake venom.” With its clotting factors spent, the blood can lose its ability to clot, and the coagulopathy “can be complicated by serious and life-threatening haemorrhage.”

The laboratory picture Isbister describes is “elevated D-dimer, prolonged prothrombin time, and low fibrinogen” — the medical meaning behind the fifth bullet. Prothrombin time is the PT/INR test, and fibrinogen has its own blood test. VICC follows bites from vipers, from some elapids (the cobra family) including Australian elapids, and from a few rear-fanged colubrid snakes (Maduwage 2014).

VICC and DIC are kept apart

Medscape lists disseminated intravascular coagulation (DIC) and snake venom poisoning as separate bullets, and the snakebite literature keeps them apart too. Isbister’s review is titled “Snakebite doesn’t cause disseminated intravascular coagulation.” It explains that VICC shares DIC’s raised D-dimer and low fibrinogen but not its “evidence of systemic microthrombi and end-organ failure”; that VICC comes on and resolves quickly; and that it is set off by the venom’s toxins, whereas clotting in DIC is driven by the body’s tissue factor pathway. In some patients VICC comes with a related condition, thrombotic microangiopathy, marked by acute kidney failure, a low platelet count and broken red blood cells.

Antivenom is the main treatment. Maduwage and Isbister’s review of the clinical studies found 25 randomised trials comparing antivenoms, doses or add-on treatments, none of them against placebo, and concluded that there is “little high-quality evidence” on how well antivenom works for VICC; in the studies with comparison groups it worked for some snakes but not others. Heparin did not improve outcomes in the studies reviewed, and fresh frozen plasma appeared to speed recovery from the coagulopathy.

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10. Dr. Ardis’s Sources

1. Culture Apothecary with Alex Clark (a Turning Point USA podcast), “Nicotine Is NOT the Villain: What Big Pharma Hides From Parents | Dr. Bryan Ardis, DC,” aired May 2025 (about one hour). The D-dimer passage runs from 34:32 to 36:17, in the chapter titled “What is a D-Dimer Test?”; the Karikó–Weissman passage is at 29:03. Quoted from the episode’s auto-generated read-along transcript.
2. Watch the Water 2, a Stew Peters film released in May 2023 — full transcript of Dr. Ardis’s interview, published January 15, 2024. The transcript’s publisher adds commentary between the spoken passages; only Dr. Ardis’s spoken words are quoted on this page.
3. Medscape, “D-Dimer” (Laboratory Medicine; updated February 22, 2022) — the article whose five bullets he reads out.
4. His show’s clip “Covid Vax Synthetic Snake Venom Research Funded by NIH Grant to mRNA Scientists Katalin Kariko and Drew Weissman 2008 & 2011” (section 5).
5. The Dr. Ardis Show — official site

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Key Research Papers

1. Karikó K, Muramatsu H, Welsh FA, et al. (2008). Incorporation of pseudouridine into mRNA yields superior nonimmunogenic vector with increased translational capacity and biological stability. Mol Ther. — PubMed PMID: 18797453
2. Anderson BR, Muramatsu H, Jha BK, et al. (2011). Nucleoside modifications in RNA limit activation of 2'-5'-oligoadenylate synthetase and increase resistance to cleavage by RNase L. Nucleic Acids Res. — PubMed PMID: 21813458
3. Adam SS, Key NS, Greenberg CS (2009). D-dimer antigen: current concepts and future prospects. Blood. — PubMed PMID: 19008457
4. Righini M, Van Es J, Den Exter PL, et al. (2014). Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study. JAMA. — PubMed PMID: 24643601
5. Tang N, Li D, Wang X, Sun Z (2020). Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia. J Thromb Haemost. — PubMed PMID: 32073213
6. Zhang L, Yan X, Fan Q, et al. (2020). D-dimer levels on admission to predict in-hospital mortality in patients with Covid-19. J Thromb Haemost. — PubMed PMID: 32306492
7. Isbister GK (2010). Snakebite doesn't cause disseminated intravascular coagulation: coagulopathy and thrombotic microangiopathy in snake envenoming. Semin Thromb Hemost. — PubMed PMID: 20614396
8. Maduwage K, Isbister GK (2014). Current treatment for venom-induced consumption coagulopathy resulting from snakebite. PLoS Negl Trop Dis. — PubMed PMID: 25340841

PubMed Topic Searches

1. PubMed: D-dimer and fibrin degradation
2. PubMed: Age-adjusted D-dimer cutoff
3. PubMed: Venom-induced consumption coagulopathy

External Authoritative Resources

• Medscape: D-Dimer — Reference Range, Interpretation, Collection and Panels (updated February 22, 2022) — the article whose five bullets Dr. Ardis reads; sections 3, 6 and 7 quote it.
• Full transcript of Dr. Ardis’s interview in Watch the Water 2 (published January 15, 2024) — the source of the film quotations on this page.
• Culture Apothecary with Alex Clark, “Nicotine Is NOT the Villain: What Big Pharma Hides From Parents | Dr. Bryan Ardis, DC” (May 2025) — the podcast quoted in sections 1, 4 and 5.

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Connections

• All Notable Doctors
• Dr. Bryan Ardis Hub — the wing’s main page: his nicotine hypothesis and snake-venom theory
• Snake Venom Phosphodiesterase in the Karikó–Weissman Papers — the next step in his chain: the papers’ exact sentences beside his words
• From Pseudouridine to the COVID-19 Vaccines — how the Karikó–Weissman discovery led to the mRNA vaccines
• The Snake Venom Hypothesis — his wider venom argument from the first Watch the Water film
• Cobra Venom and Nicotine — his account of the receptor that venom and nicotine share
• Vaccine-Injury Recovery — the post-vaccination lab panel set out there includes D-dimer
• D-Dimer Test — the site’s full page on the test, cutoffs and results
• How Blood Clots Dissolve (Animation) — watch plasmin cut a clot and D-dimer rise
• How Blood Clots, and How Thinners Stop It (Animation) — the clotting chain, warfarin and heparin, step by step
• Deep-Vein Thrombosis — the clot the D-dimer test is mainly used to rule out
• Pulmonary Embolism — a clot lodged in the lungs, the test’s other main rule-out use
• Disseminated Intravascular Coagulation — Medscape’s fourth bullet

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