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Test Code LABYMCRO Y Chromosome Microdeletions, Molecular Detection

Additional Codes

Test Name in EPIC EPIC Test Code Mnemonic Mayo Test ID


Useful For

Evaluating men with azoospermia, severe oligozoospermia, or otherwise unexplained male factor infertility

Genetics Test Information

Tests for the presence of microdeletions in the AZFa, AZFb, and AZFc regions of the Y chromosome.

Method Name

Polymerase chain reaction (PCR) is used to test DNA for the presence of microdeletions of the Y chromosome (region AZFa, AZFb, and AZFc).

Reporting Name

Y Microdeletion

Specimen Type


Shipping Instructions

Specimen preferred to arrive within 96 hours of draw.

Specimen Required

Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories for instructions for testing patients who have received a bone marrow transplant.

Specimen Type: Whole blood


Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)

Reject Due To

No specimen should be rejected.

Clinical Information

Yq microdeletions involving some or all of the azoospermic factor (AZF) region are the most frequently identified cause of spermatogenic failure in chromosomally normal men with nonobstructive azoospermia (3%-15%) or severe oligospermia (6%-10%). Among unselected infertile males, the overall frequency of Yq microdeletions is approximately 3%. The relative frequency of Yq microdeletions makes the evaluation for them an important aspect of the diagnostic work up in infertile males, especially those with azoospermia or severe oligospermia.


Most cases of Yq microdeletions occur de novo, and due to the consequential infertile phenotype, they are typically not transmitted. However, in cases where assisted reproductive technology (example: testicular sperm extraction followed by intracytoplasmic sperm injection) is used to achieve viable pregnancy, all male offspring born to a microdeletion carrier will carry the deletion and may be infertile.


Men testing positive for 1 or more microdeletions who are enrolled in an in vitro fertilization treatment program may wish to consider alternative options to intracytoplasmic sperm injection (eg, donor sperm) and consultation with an experienced reproductive endocrinologist and medical geneticist is recommended.


Most Y microdeletions are the result of homologous recombination between repeated sequence blocks. Testing for deletions involves investigating for the presence or absence of markers located within nonpolymorphic regions of the AZF region.


An interpretive report will be provided.


This assay will not detect all of the causes of infertility or azoospermia. Therefore, the absence of a detectable microdeletion does not rule out the presence of other genetic or nongenetic factors that may be the cause of clinical findings.


Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in our interpretation of results may occur if information given is inaccurate or incomplete.


Rare polymorphisms exist that could lead to false-negative or false-positive results. If results obtained do not match the clinical findings, additional testing should be considered.


In rare cases, DNA alterations of undetermined significance may be identified.


A genetic consultation is recommended for all patients undergoing this testing. Additional consultation with a reproductive endocrinologist/urologist to discuss reproductive options is recommended when a deletion is detected.

Supportive Data

Validation studies done at Mayo Clinic on a series of known fertile and infertile specimens provided the following results. Of 111 DNA specimens from known fertile men, 110 gave unequivocal negative results demonstrating clinical specificity of 99%. A series of 19 specimens from females (negative controls) were all negative, as expected. In a small series of specimens from 4 men being treated for male factor infertility, no deletions were found (which may be expected given a reported prevalence of 7% for microdeletions in unselected male infertility patients). Seven specimens were mailed in from outside laboratories (3 of which were sent as part of an external quality assessment scheme organized by the European Academy of Andrology) with known deletions in either AZFa, AZFb, or AZFc. Using our assay, all were diagnosed correctly to give an analytical sensitivity of 100%.

Method Description

Multiplex PCR and agarose gel electrophoresis are used to test DNA for the presence of microdeletions in the AZFa, AZFb, and AZFc regions of the Y chromosome.(Simoni M, Bakker E, Krausz C: EAA/EMQN best practice guidelines for molecular diagnosis of y-chromosomal microdeletions. State of the art 2004 Int J Androl 2004;Aug 27[4]:240-249)

Day(s) and Time(s) Performed

Friday; 2 p.m.

Analytic Time

5 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

81403-DAZ/SRY (deleted in azoospermia and sex determining region Y) (eg, male infertility), common deletions (eg, AZFa, AZFb, AZFc, AZFd)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
YMCRO Y Microdeletion In Process


Result ID Test Result Name Result LOINC Value
53364 Result Summary 50397-9
53365 Result 82939-0
53366 Interpretation 69047-9
53367 Specimen 31208-2
53368 Source 31208-2
53369 Released By 18771-6

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.


1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. Molecular Genetics: Congenital Inherited Diseases Patient Information (T521) in Special Instructions

Specimen Minimum Volume

1 mL