Introduction: Who Should Undergo Diagnostics and When

If you notice a new rash that looks like pimples or blisters, particularly if it appears on your face, hands, feet, genitals, or around your mouth, it’s time to consider getting tested for Monkeypox. This is especially important if you’ve recently been in close physical contact with someone who has Monkeypox or if you’ve traveled to areas where the disease is spreading. The virus doesn’t discriminate—anyone can catch it through close contact, so don’t hesitate to reach out to a healthcare provider if something seems unusual.^[1]

Healthcare professionals recommend seeking diagnostic testing as soon as symptoms appear. Early symptoms often resemble flu-like illness, including fever, headache, muscle aches, and swollen lymph nodes. These typically show up within three to seventeen days after you’ve been exposed to the virus, though the average is about one to two weeks. The timing matters because Monkeypox becomes contagious from the moment symptoms start until all the rash lesions have completely healed, which means all scabs have fallen off and fresh skin has formed underneath.^[3]

Certain groups of people should be particularly alert and seek testing promptly. If you’re pregnant, have a weakened immune system, are a young child (especially under eight years old), or have a history of skin conditions like eczema or atopic dermatitis, you may be at higher risk for more severe disease. Healthcare workers, household members of infected people, and anyone who has had intimate physical or sexual contact with someone showing symptoms should also prioritize getting tested.^[4]

It’s worth noting that not everyone with Monkeypox develops all the typical symptoms. Some people only get a rash without any fever or other warning signs, while others experience flu-like symptoms first and the rash appears days later. A few people may even have flu-like symptoms but never develop a visible rash at all. This variability is exactly why medical testing is so important—it removes the guesswork and provides a definite answer.^[4]

Diagnostic Methods: How Healthcare Providers Identify Monkeypox

When you visit a healthcare provider with concerns about Monkeypox, they will start with a careful physical examination and ask detailed questions about your symptoms and recent activities. They’ll want to know when your symptoms began, whether you’ve had close contact with anyone who has Monkeypox, and if you’ve traveled recently. This conversation helps them determine whether testing is appropriate and what other conditions they might need to rule out.^[3]

The gold standard for diagnosing Monkeypox is a laboratory test called polymerase chain reaction, or PCR testing. This is a molecular test that detects the virus’s genetic material—specifically its DNA—in samples taken from your body. PCR testing is highly accurate and can confirm whether the Monkeypox virus is present even when symptoms are just beginning to appear. The test works by amplifying tiny amounts of viral DNA until there’s enough to detect and identify.^[1][4]

To perform PCR testing, healthcare providers need to collect specimens from the rash lesions themselves. The preferred method is to swab the fluid or pus from the blisters, or to take samples from the crusted scabs. This is done using a sterile swab, similar to the ones used for throat swabs but applied gently to the skin lesions. If you have lesions in your mouth, throat, rectum, or genital areas, samples may be taken from those locations as well. The healthcare provider will typically collect samples from multiple lesions if possible, as this increases the accuracy of the test.^[8]

In some cases, particularly when lesions are not easily accessible or when additional information is needed, other types of samples may be collected. These can include swabs from the throat or nose, blood samples, or samples of saliva or other bodily fluids. However, skin lesion samples remain the most reliable source for detecting the virus. After collection, these specimens are carefully packaged and sent to specialized laboratories equipped to handle infectious materials safely.^[8]

Healthcare providers must also consider other diseases that can cause similar symptoms. This process, called differential diagnosis, is crucial because several other infections can produce rashes that look like Monkeypox. Chickenpox, for example, causes a blistering rash that can appear similar, especially in the early stages. Other conditions that might be confused with Monkeypox include measles, bacterial skin infections, scabies, syphilis, and certain drug allergies that cause skin reactions.^[9]

One distinguishing feature that helps healthcare providers identify Monkeypox is the presence of swollen lymph nodes, which is medically called lymphadenopathy. Unlike chickenpox or smallpox, Monkeypox commonly causes the lymph nodes—particularly those in the neck, armpits, or groin—to become enlarged and tender. This symptom typically appears early in the illness and can be an important clue that points toward Monkeypox rather than other similar diseases.^[8]

The timing and progression of the rash also provide diagnostic clues. The Monkeypox rash goes through very specific stages over two to four weeks. It starts as flat, red spots, then becomes raised bumps, which turn into blisters filled with clear fluid. These blisters then fill with pus, eventually forming a crust or scab before healing. What’s particularly characteristic of Monkeypox is that all the lesions in a given area tend to be at the same stage of development at the same time, unlike chickenpox where you might see spots, blisters, and scabs all mixed together.^[3][4]

Blood tests can provide supporting information but are generally not used as the primary method to diagnose active Monkeypox infection. However, antibody tests—which detect proteins your immune system makes in response to the virus—can be helpful in certain situations. These tests can show whether you were exposed to Monkeypox in the past and possibly developed immunity. But antibody tests have limitations: they can’t tell you if you currently have an active infection, and they may show cross-reactions with other viruses in the same family, like smallpox or cowpox.^[8]

The entire diagnostic process, from collecting samples to receiving results, typically takes several days. During this waiting period, healthcare providers will usually advise you to isolate yourself from others as a precaution. This means staying in a separate room if possible, avoiding close physical contact with household members and pets, and following specific hygiene practices to prevent the potential spread of the virus.^[10]

Diagnostics for Clinical Trial Qualification

When researchers conduct clinical trials to test new treatments or vaccines for Monkeypox, they need to be absolutely certain about which patients actually have the disease. This requires even more rigorous diagnostic testing than might be used in routine clinical practice. Clinical trials use standardized testing protocols to ensure that every participant meets specific, clearly defined criteria before they can be enrolled in the study.^[10]

For clinical trial participation, confirmed laboratory diagnosis through PCR testing of lesion samples is typically mandatory. Researchers cannot rely on clinical symptoms alone or presumptive diagnosis—there must be definitive laboratory proof that the Monkeypox virus is present. This is because clinical trial results need to be precise and scientifically valid. If patients without actual Monkeypox were accidentally included, it could skew the results and make a treatment appear more or less effective than it really is.^[10]

Clinical trials may also require additional diagnostic information beyond just confirming the presence of the virus. Researchers often need to know which specific clade of Monkeypox virus a patient has—that is, which genetic family the virus belongs to. There are two main types: Clade I, which has historically been found in Central Africa and tends to cause more serious illness, and Clade II, which has been responsible for the global outbreak that began in 2022 and is generally less severe. Within these clades are subclades, such as Ia, Ib, IIa, and IIb, each with slightly different characteristics.^[2][4]

Determining which clade of the virus is present requires specialized genetic testing called sequencing, which analyzes the virus’s genetic code in detail. This information helps researchers understand whether different strains of the virus respond differently to treatments, and it’s particularly important now that both Clade I and Clade II are circulating in different parts of the world. Not every diagnostic laboratory can perform this advanced testing—it typically requires specialized equipment and expertise found only in reference laboratories or research institutions.^[2]

Clinical trials testing treatments for Monkeypox also require careful monitoring of how severe a patient’s illness is. Researchers use standardized scales and criteria to categorize patients as having mild, moderate, or severe disease. These assessments look at factors like the number and location of lesions, whether the patient has complications like bacterial skin infections, eye involvement, or breathing problems, and whether the patient has conditions that put them at higher risk, such as severe immune suppression or pregnancy.^[10]

Participants in clinical trials typically need to undergo repeated diagnostic testing throughout the study period. This isn’t just a one-time test at enrollment. Researchers collect samples at multiple time points to track how quickly the virus clears from the body, whether viral levels decrease in response to treatment, and when patients are no longer infectious. This serial testing provides crucial data about whether a treatment is actually working and how quickly it takes effect.^[10]

Blood tests measuring immune responses may also be part of clinical trial diagnostics. These tests check for antibodies against the Monkeypox virus at different stages of illness and treatment. By measuring antibody levels before, during, and after treatment, researchers can understand how the immune system is responding and whether treatments or vaccines are stimulating the desired immune protection. This is particularly important for vaccine trials, where the main goal is to see if the vaccine triggers a protective immune response.^[8]

Clinical trials may also require additional baseline diagnostic tests to ensure participant safety. Before enrolling someone in a trial, researchers typically perform blood tests to check liver and kidney function, blood cell counts, and other health indicators. If the treatment being tested could potentially have certain side effects, specific monitoring tests will be required throughout the study. For example, if an antiviral drug being tested could affect the kidneys, regular kidney function tests would be mandatory.^[10]

The diagnostic standards for clinical trials are deliberately more stringent than those used in routine care because research must meet the highest scientific and ethical standards. While this means not every patient can participate in trials, it also means that when treatments are eventually approved based on trial results, we can trust that they’ve been properly tested in patients who genuinely had the disease.