Introduction: When to Seek Diagnostic Testing

Anyone experiencing symptoms that could suggest acute myeloid leukaemia should seek medical attention promptly. Because this type of blood cancer develops and progresses rapidly, early diagnosis can make a significant difference in treatment outcomes^[2]. You should consult a doctor if you notice persistent symptoms such as ongoing fatigue that doesn’t improve with rest, frequent infections that won’t go away, unexplained bruising or bleeding without clear cause, or fever that continues despite treatment^[4].

In the early stages, symptoms of acute myeloid leukaemia may feel similar to having a cold or flu that simply won’t resolve. However, because this is an aggressive cancer, symptoms typically worsen quickly and new signs appear^[2]. Many people first visit their general practitioner when they notice these troubling symptoms, while others may go directly to accident and emergency departments depending on how severe their symptoms have become^[6].

The symptoms that should prompt you to seek diagnostic testing include dizziness, easy bruising or bleeding (including frequent nosebleeds and bleeding gums), extreme tiredness, feeling unusually cold, night sweats, frequent infections, headaches, loss of appetite, unexplained weight loss, pale skin, shortness of breath, swollen lymph nodes, weakness, bone or back pain, tiny red spots on the skin, and wounds that don’t heal^[2]. If you experience several of these symptoms together or notice they are getting worse, it’s important not to delay seeking medical evaluation.

Classic Diagnostic Methods for Identifying AML

Diagnosing acute myeloid leukaemia typically begins with an initial examination where your doctor checks for physical signs such as bruising, bleeding in the mouth or gums, infection, and swollen lymph nodes^[12]. This physical assessment helps the doctor understand what additional tests might be needed to confirm or rule out a diagnosis.

Blood Tests

Blood tests are usually the first laboratory examinations performed when AML is suspected. The most common initial test is called a complete blood count, which measures the number of different types of blood cells in a sample taken from your vein^[12]. This test can reveal whether you have too many or too few white blood cells, and often shows that there aren’t enough red blood cells or platelets^[5].

Another important blood test looks specifically for immature white blood cells called myeloblasts in your blood. These cells typically shouldn’t be present in the bloodstream, but they appear in the blood of people with acute myeloid leukaemia^[12]. When myeloblasts are found in blood samples, it strongly suggests the presence of AML and indicates the need for further testing.

Blood tests may also be performed to check for other conditions that can affect treatment planning. These might include checking your electrolyte levels to screen for a condition called tumor lysis syndrome, measuring lactate dehydrogenase levels, and evaluating your blood’s ability to clot properly to check for a condition called disseminated intravascular coagulation^[11].

Bone Marrow Aspiration and Biopsy

The definitive diagnosis of acute myeloid leukaemia is made through bone marrow examination^[3]. This procedure involves two related tests: bone marrow aspiration and bone marrow biopsy. During a bone marrow aspiration, a healthcare professional uses a thin needle to remove a small amount of liquid bone marrow, usually from a spot in the back of the hip bone^[12]. A bone marrow biopsy is often performed at the same time, removing a small piece of bone tissue along with the marrow inside it.

The samples collected during these procedures are examined in several ways. First, specialists look at the cells under a microscope to determine what percentage are blast cells. When more than 20% of cells in the bone marrow are myeloblasts, this confirms the diagnosis of acute myeloid leukaemia^[11]. The bone marrow is like a production facility for blood cells, and in AML, this factory has started producing far too many abnormal, immature cells instead of healthy ones.

Advanced Laboratory Analysis

Beyond simply counting blast cells, the bone marrow samples undergo sophisticated laboratory analysis to understand the specific characteristics of the leukaemia. Flow cytometry is a technique that helps identify specific markers on the surface of cells, which helps classify the exact subtype of AML^[11]. This information is important because different subtypes may respond differently to treatment.

Cytogenetic testing examines the chromosomes inside the leukaemia cells to look for any abnormalities or changes^[11]. Chromosomes are structures that contain your genetic information, and certain chromosome changes can help predict how aggressive the disease might be and how well it might respond to treatment. This testing helps doctors categorize AML into risk groups: favorable, intermediate, or unfavorable^[3].

Molecular testing looks for mutations in specific genes within the cancer cells. Recent guidelines have emphasized the importance of this molecular characterization for understanding AML and planning treatment^[3]. Certain gene mutations can affect prognosis and may also make some patients eligible for specific targeted therapies. For example, mutations in genes with names like TET2, NRAS, and others can be identified through these tests^[11].

Additional Diagnostic Procedures

After AML has been diagnosed through blood and bone marrow tests, additional examinations may be performed to determine if the cancer has spread to other parts of the body^[5]. A lumbar puncture, also known as a spinal tap, may be done to check if leukaemia cells have spread to the fluid surrounding the brain and spinal cord. During this procedure, you typically lie on your side with your knees drawn up to your chest, and a needle is inserted into the lower back to collect a sample of cerebrospinal fluid for testing^[12].

Imaging tests such as chest X-rays or CT scans may be ordered if there are concerns that the leukaemia has affected other organs or if complications need to be evaluated. While imaging isn’t typically used to diagnose AML itself, it can help assess the overall health status and identify any related problems.

Diagnostics for Clinical Trial Qualification

When considering participation in clinical trials for acute myeloid leukaemia, patients typically undergo a standardized set of diagnostic tests to determine eligibility. Clinical trials have specific criteria for enrollment, and comprehensive testing helps ensure that participants are suitable candidates for the experimental treatments being studied.

The standard diagnostic tests for clinical trial qualification include all the basic diagnostic procedures used to confirm AML: complete blood counts, bone marrow aspiration and biopsy, flow cytometry, cytogenetic analysis, and molecular testing^[11]. However, clinical trials may require additional or more detailed analysis of these samples to identify patients with specific disease characteristics that the trial is designed to study.

Molecular characterization is particularly important for many modern clinical trials. The 2022 European LeukemiaNet consensus guidelines provide a framework for classifying AML based on mutational profiles, and many trials use these classifications to determine eligibility^[3]. Patients may need testing for specific gene mutations that the trial’s experimental treatment is designed to target. For example, some clinical trials specifically enroll patients whose leukaemia cells have particular genetic mutations that make them more likely to respond to a new targeted therapy.

Assessment of overall health status is another important component of clinical trial eligibility. Doctors often use something called the Eastern Cooperative Oncology Group performance status to evaluate how well a patient can carry out daily activities^[11]. This scoring system helps determine whether a patient is healthy enough to tolerate the trial’s treatment protocol. Blood chemistry tests to check kidney and liver function, heart function tests such as electrocardiograms, and other organ function assessments may be required.

Clinical trials may also require specific tests to measure measurable residual disease, which refers to leukaemia cells that remain in very small numbers after treatment but can only be detected using very sensitive laboratory techniques like flow cytometry or polymerase chain reaction (PCR)^[14]. These tests can identify whether microscopic amounts of disease remain even when standard tests show the bone marrow appears normal.

Before enrolling in a clinical trial, patients should expect to undergo a thorough evaluation that may include repeating some diagnostic tests even if they were recently performed. This ensures that the most current and accurate information about the disease is available. The trial team will explain exactly which tests are needed and why they’re important for determining eligibility and monitoring response during the study.