VNTR (Variable Number of Tandem Repeats) are minisatellites, that is, nucleotide patterns ranging from 10 to 100 bases typically repeated 5-50 times and located in certain regions of a given genome. Specific primers are used to PCR-amplify fragment that contain VNTRs. Their size of the fragments are measured on a capillary sequencer and by hence the number of repeats are deducted. Each variation of length represents an allele.
MLVA (Multiple Loci VNTR Analysis) use the length polymorphism of the VNTRs as a molecular method for the typing of organisms
MIRU (Mycobacterial Interspersed Repetitive Units) is a specific name for the MLVA analysis of the Mycobacterium tuberculosis complex. Similarly, the term SIRU is used for Staphylococcus aureus typing.