Request / Find a Test Tool

The National Genomic Test Directories specify which genomic tests are commissioned by the NHS in England, to be delivered by Genomic Laboratory Hubs.

This tool allows clinical teams to search all of the genomic tests available to patients through the National Testing Directory. From here you can find out more details about each test and information about how to order them. These tests can only be ordered by clinical teams, if you are a patient looking to request a test please speak to your clinical team directly.

Chromosomal mosaicism – karyotype

Clinical Indication ID & Name


Chromosomal mosaicism - karyotype

Test Group


Test code


Test name


Target genes


Test scope


Test method/ technology


Optimal Family Structure


Eligibility Criteria

Individuals with possible mosaic chromosome abnormality requiring extended count karyotype including:
1. possible mosaic chromosome abnormality indicated by findings from conventional karyotype, microarray, WGS or other laboratory technique, OR
2. clinical features strongly suggestive of a specific chromosomal phenotype, for example Down syndrome, in whom conventional testing is negative

Commissioning group


Overlapping idications

• R343 Chromosomal mosaicism - microarray should be used where a microarray is indicated

Address for samples/request forms

North Thames GLH, Rare & Inherited Disease Genomic Laboratory
Specimen Reception, Level 5 Barclay House, 37 Queen Square,
London WC1N 3BH

Contact with queries

Supporting documents


Education resources


Service updates


Consent record

See consent guidance in test request form

Sample requirements

See sample guidance in test request form