April 8th 2026
–
Riordan Clinic
–
Riordan Approach Using HOT-UBI + IVC
Written by Ron Hunninghake, MD
Over the past several years, we have been seeing a growing number of patients who never fully recover from a COVID infection…be it severe or just mildly debilitating. Months or even years later, they continue to experience fatigue, brain fog, breathing difficulties, digestive problems, and a long litany of other lingering symptoms that can be very disabling.
This pattern has come to be known as “Long COVID”, a condition now estimated to affect more than 330 million people globally. Although this is now an accepted medical diagnosis, it unfortunately lacks a clear understanding of its underlying cause or causes. Thus, most treatments can address only symptoms…but not the cause. Hence, Long COVID often means “long suffering.”
Emerging research suggests that Long COVID may involve changes in the micro-vascular system that can occur somewhat randomly throughout the body. This is a clue as to why there is so much symptom variability from patient to patient… and why it is closely related to the infamous behavior of the long COVID spike protein.
The Role of Spike Protein in Long COVID
The spike protein is known to be closely associated with the COVID virus. This novel protein typically interacts with ACE2 receptors that are widely distributed throughout the body. These receptors are especially common along the inner lining of blood vessels.
When spike proteins interact with these receptors, inflammatory signals may develop within the inner lining of the blood vessel. Healthy blood vessels normally provide a smooth pathway for circulation. You might picture it like a well-paved highway where blood cells can move freely.
When inflammation develops along the vessel lining, that smooth surface may become rough and reactive. Instead of a clear roadway, the circulation system may begin to resemble a damaged highway with debris scattered along the path.
In this environment, very small but destructive fibrin structures may begin forming in the linings of these small vessels. These structures are now referred to as “microclots” and NETs. (See below, the Journal of Medical Virology. October 2025.)
What Are Microclots in Long COVID
To understand why researchers are paying attention to microclots in Long COVID, it helps to look more closely at what scientists mean by the term.
Unlike larger clots associated with strokes or heart attacks, microclots are microscopic and cannot be easily detected with standard imaging.
The smallest blood vessels in the body are capillaries. These vessels are so narrow that red blood cells often move through them one at a time. Since normal blood flow means oxygen easily reaches all our tissues, microclots can decrease blood flow in the body’s smallest vessels, robbing the cells they feed of optimal levels of oxygen. Physicians sometimes refer to this as localized or “spotty” hypoxia.
Uneven oxygen delivery may help explain symptoms such as fatigue, brain fog, shortness of breath, or muscle discomfort. Researchers are studying whether these micro changes in the circulation play a role in these lingering symptoms.
How NETs May Contribute to Microclots
Microclots may not be the only factor involved. Researchers have also been studying a related immune process that may interact with these clots called NETs, or neutrophil extracellular traps.
NETs are webs of DNA released by immune cells to help trap microbes during infection. In normal circumstances, they play an important role in immune defense.
When NET formation becomes excessive, these sticky DNA webs may interact with fibrin proteins in the bloodstream. This interaction may contribute to the persistence of microclots.
Elevated NET markers have been observed in some individuals experiencing Long COVID symptoms.
A D-dimer Test Detects Microclots
The D-dimer test measures fragments that appear in the bloodstream when fibrin clots break down.
Rather than detecting the clot itself, the test detects evidence of clotting activity.
For that reason, the D-dimer test can function somewhat like a smoke detector. It does not show the fire directly but indicates that minute clotting activity may be present.
Many laboratories consider levels below 0.50 mg/L (or 500ng/mL) to fall within the standard reference range. Some clinicians prefer to see levels below 0.35 mg/L (or 300ng/mL) when possible. Healthy young adults have levels as low as 0.20 mg/L (or 200ng/mL).
At Riordan Clinic, the D-dimer test is being researched as a possible Long COVID marker. While results are encouraging, we have found that a normal D-dimer does not necessarily rule out the Long COVID syndrome.
The HOT-UBI Approach at Riordan Clinic
If circulation and oxygen delivery are part of the story, an important question becomes how clinicians might support these processes during recovery.
One approach used at Riordan Clinic is Hematogenic Oxidation Therapy, or HOT. This therapy is a specialized form of ultraviolet blood irradiation in which a small portion of the patient’s blood is withdrawn, exposed to ultraviolet light and 100% oxygen under pressure, and then slowly reinfused into the circulation.
The goal is to help support circulation, oxygen delivery, and immune system signaling. The procedure is under a 1955 free-use patent.
Because only a small amount of blood is treated directly, the therapy is intended to stimulate broader responses throughout the body.
At Riordan Clinic, HOT is a combined oxygen/ultraviolet blood irradiation with other integrative therapies. The combined approach is sometimes referred to as HOT-UBI.
Researchers and clinicians continue to study how combination therapies like this might improve microcirculation and oxygen delivery to support recovery in people experiencing Long COVID.
Adding Intravenous Vitamin C: HOT-UBI + IVC
Following HOT-UBI therapy, we are now recommending that our co-learners receive intravenous vitamin C.
Vitamin C functions as an electron donor and supports the body’s antioxidant balance. Because it can enter many tissues throughout the body, including the brain, vitamin C may help support normal cellular metabolism and speed up recovery after injury
As circulation improves and inflammatory debris begins to clear, some individuals may experience temporary fatigue or mild flu-like symptoms.
This reaction is sometimes referred to as the Herxheimer response. It occurs when the body clears biological debris faster than detoxification pathways can process it. These symptoms are typically temporary and resolve as the body restores balance.
By following their HOT-UBI treatment with IVC, the hope is to reduce any likelihood of a Herxheimer response.
One Patient’s Experience
One patient in her sixties had experienced persistent symptoms following COVID for several years. Generalized fatigue, along with stiffness and discomfort in her legs, made it difficult to kneel in church or walk upstairs comfortably.
Even routine errands, such as grocery shopping, required careful planning due to severe fatigue and muscle discomfort.
After receiving two HOT-UBI treatments combined with intravenous vitamin C, she reported significant improvement in her symptoms. She was again able to kneel in church, walk upstairs, and visit several stores during a single outing.
Individual experiences vary, and ongoing research continues to explore these approaches.
In our clinic, we continue learning from each patient who walks through the door. Each case adds another piece to the puzzle of how circulation, immune response, and cellular metabolism interact during recovery.
Looking Ahead
Long COVID remains an evolving area of research. Physicians and scientists continue exploring how inflammation, circulation, and cellular energy interact following viral infection.
By carefully following the biological breadcrumbs, clinicians may uncover better ways to support individuals navigating this complex condition.
Frequently Asked Questions
What are microclots in Long COVID?
Microclots are tiny clumps of fibrin circulating in the bloodstream that may affect blood flow in the body’s smallest vessels.
Why do people with Long COVID feel fatigued?
Fatigue may be related to several factors, including inflammation, changes in circulation, and reduced oxygen delivery to tissues.
What are NETs?
NETs, or neutrophil extracellular traps, are webs of DNA released by immune cells to trap microbes during infection.
What does a D-dimer test measure?
A D-dimer test measures fragments produced when blood clots break down in the body.
What is HOT-UBI + IVC therapy?
HOT-UBI refers to Hematogenic Oxidation Therapy (HOT) combined with ultraviolet blood irradiation. A small portion of blood is exposed to ultraviolet light and oxygen before being returned to circulation, as part of an integrative clinical approach being explored to support circulation and immune balance. The Riordan IVC treatment is added to reduce the likelihood of a Herxheimer, or rapid healing response.
References
- Levy TE. Curing Long COVID and Associated Hypercoagulation. Shanghai Salon Zoom Dialogue, February 24, 2026.
- Pretorius E, et al. Circulating microclots are structurally associated with neutrophil extracellular traps and are elevated in Long COVID patients. Journal of Medical Virology. October 2025.
- Knott EK. Historical observations on ultraviolet blood irradiation therapy.
Considering HOT-UBI + IVC?
If you’re new to Riordan Clinic, you’re welcome to schedule an appointment at our Wichita or Overland Park, Kansas location to discuss your health goals and explore whether HOT-UBI + IVC may be a good fit.
If you’re a current Riordan Clinic co-learner, talk with your provider about whether incorporating HOT-UBI + IVC into your existing care plan may be appropriate.
The post New Hope for Long COVID at Riordan Clinic appeared first on Riordan Clinic.
Read the full article here:
https://riordanclinic.org/2026/04/new-hope-for-long-covid-at-riordan-clinic-2/
