single-cell-rna-qc

When to Use This Skill

Use when users:

• Request quality control or QC on single-cell RNA-seq data
• Want to filter low-quality cells or assess data quality
• Need QC visualizations or metrics
• Ask to follow scverse/scanpy best practices
• Request MAD-based filtering or outlier detection

Supported input formats:

• .h5ad files (AnnData format from scanpy/Python workflows)
• .h5 files (10X Genomics Cell Ranger output)

Default recommendation: Use Approach 1 (complete pipeline) unless the user has specific custom requirements or explicitly requests non-standard filtering logic.

Approach 1: Complete QC Pipeline (Recommended for Standard Workflows)

For standard QC following scverse best practices, use the convenience script scripts/qc_analysis.py:

python3 scripts/qc_analysis.py input.h5ad

## Workflow Steps

The script performs the following steps:

1. **Calculate QC metrics** - Count depth, gene detection, mitochondrial/ribosomal/hemoglobin content
2. **Apply MAD-based filtering** - Permissive outlier detection using MAD thresholds for counts/genes/MT%
3. **Filter genes** - Remove genes detected in few cells
4. **Generate visualizations** - Comprehensive before/after plots with threshold overlays