New Alzheimer’s Blood Test

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Why in News?

Researchers at Lund University, Sweden, have developed a new blood test, PrecivityAD2, which is about 90% accurate in diagnosing Alzheimer's Disease (AD) even at early stages of mild cognitive impairment.

Significance: This test is a breakthrough in the diagnosis of AD as it offers a non-invasive, simpler, and cost-effective alternative to the current expensive and complex diagnostic methods like amyloid or Tau PET scans. Traditionally, cerebrospinal fluid is obtained via lumbar puncture for diagnosis, making the blood test a revolutionary advancement.

Impact on Diagnosis and Treatment: Blood tests are set to transform the detection, diagnosis, and treatment of AD. They could replace invasive PET scans, providing a first-line defense in diagnosing the disease. With easier and more affordable testing, early diagnosis and treatment of AD could be significantly improved.

Accuracy and Validation: In studies involving 1,123 patients, the blood test showed an accuracy of 91% in identifying clinical AD. This is a substantial improvement compared to the diagnostic accuracy of 61% in primary care physicians and 73% in dementia specialists using traditional methods.

Future Prospects and Challenges: Researchers advocate for further studies on the clinical impact of these biomarkers. While costs are expected to decrease over time, making the test more affordable, in India, MRI and PET scans remain the primary diagnostic tools due to limited availability of the blood test.

Revisiting Sub-Quotas for Scheduled Castes

Why in News?

A seven-judge bench of the Supreme Court has ruled that states can sub-divide Scheduled Castes (SC) for sub-quotas within the reservation for Dalits. This overturns a 2004 judgment by a five-judge bench which held such sub-classification as impermissible without parliamentary approval.

Historical Context: The Andhra Pradesh Scheduled Castes (Rationalisation of Reservation) Ordinance, 1999, aimed to create sub-groups within SCs, assigning varying reservation percentages. This was challenged and struck down in E.V. Chinnaiah (2004), asserting that SCs constitute a single homogenous class under Article 341 of the Constitution.

Rationale for Sub-Classification: The court acknowledged differences in advancement levels among SC communities. It highlighted the need for sub-classification to ensure fair representation of weaker castes, citing empirical evidence of discrimination within SCs. Sub-classification should be based on an "intelligible differentia" and serve a rational purpose.

Views on Creamy Layer Exclusion: The creamy layer concept, applicable in OBC reservations, was discussed. Some judges supported excluding the affluent among SCs to prevent the benefits from being monopolized, while others felt it contradicted the notion of SCs as a homogenous class.

Implications: The judgment empowers states to tailor reservations to address intra-caste disparities, potentially improving representation for marginalized SC communities. However, it emphasizes that such actions should not alter the fundamental homogeneity of SCs, maintaining judicial scrutiny over such measures.