Rapid-CRISPR for Acute Promyelocytic Leukaemia Diagnosis

April 7, 2025

Acute promyelocytic leukaemia (APL) is a rare but aggressive form of leukaemia. This blood cancer arises from a genetic mutation involving the fusion of PML and RARA genes. The result is decrease in white blood cells and platelets. This reduction hampers the body’s ability to fight infections and manage bleeding. APL can cause severe internal bleeding, particularly in vital organs. Without prompt treatment, it can lead to death within days. However, early diagnosis and treatment can lead to high cure rates.

About APL

Acute promyelocytic leukaemia (APL) is classified as a subtype of acute myeloid leukaemia (AML). It represents 10-15% of newly diagnosed AML cases. The median age for diagnosis is approximately 34 years. The male-to-female ratio is about 1.5:1. Symptoms include sudden bleeding from the gums and nose, fatigue, fever, and bone pain. These symptoms can mimic other conditions, complicating diagnosis.

Diagnostic Challenges

Current diagnostic tests for APL are time-consuming and require expensive equipment. This creates barriers in smaller hospitals and rural areas. The delay in diagnosis can be fatal. Quick identification of APL is crucial for effective treatment.

The RAPID-CRISPR Test

Researchers at Tata Memorial Hospital have developed a new diagnostic test called RAPID-CRISPR. This test utilises CRISPR technology for rapid and accurate diagnosis. The test can deliver results in under three hours. It is also more cost-effective than traditional tests. Importantly, it does not require complex laboratory setups.

How RAPID-CRISPR Works

The RAPID-CRISPR test involves adding a patient’s peripheral blood sample to a test tube. The test detects the PML-RARA gene mutation responsible for APL. It cuts the mutation, triggering a detectable signal. Results appear on a simple lateral flow strip, similar to a home pregnancy test. This method allows for a diagnosis in 80% of cases using peripheral blood. In cases with low white blood cell counts, bone marrow aspiration is used.

Sensitivity and Specificity

The RAPID-CRISPR test boasts nearly 100% sensitivity and specificity. It has a very low risk of false positives or negatives. In trials with 134 clinical samples, the test accurately identified APL in every case. Its sensitivity is ten times greater than the current gold-standard test.

Accessibility and Future Prospects

Many developing countries lack resources for complex genetic testing. The RAPID-CRISPR test aims to bridge this gap. Its simplicity and affordability can ensure timely diagnosis and treatment for patients. Future developments may allow for at-home testing, broadening access even further.

Ongoing Improvements

The current version of the test uses three strips to detect three isoforms of PML-RARA. Researchers are working on optimising the assay for a single-tube reaction. This will enable detection of all isoforms with one strip, enhancing efficiency.

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