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Inhibin A

Test Codes

EPIC: LAB6887, SOFT: INH

Department

Special Chemistry

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 2.0 mL)

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8°C or 36-46°F). (Minimum Serum: 0.5 mL)

Rejection Criteria

• Plasma specimens. 
• Severely hemolyzed, lipemic or icteric specimens. 
• Specimens not collected and processed as indicated. 

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Room temperature is acceptable for a maximum of two hours. (Minimum Serum: 0.5 mL)

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Special Testing Laboratory

Performed

Monday – Friday.
Results available within 24 hours.

Reference Range

Normal Cycling Females
Early Follicular Phase (-14 to -10): 1.8-17.3 pg/mL.
Mid Follicular Phase (-9 to -4): 3.5-31.7 pg/mL.
Late Follicular Phase (-3 to -1): 9.8-90.3 pg/mL.
Mid Cycle (Day 0): 16.9-91.8 pg/mL.
Early Luteal (1 to 3): 16.1-97.5 pg/mL.
Mid Luteal (4 to 11): 3.9-87.7 pg/mL.
Late Luteal (12 to 14): 2.7-47.1 pg/mL.

IVF Peak Levels: 354.2-1690.0 pg/mL.
PCOS - Ovulatory: 5.7-16.0 pg/mL.
Postmenopausal: Less than 6.9 pg/mL.
Normal Males: Less than 2.1 pg/mL.

Test Methodology

Chemiluminescent Immunoassay.

Interpretation

• In females, Inhibin A is produced mainly by the dominant follicle in the ovary and by the corpus luteum. Levels vary during the menstrual cycle and are very low once menopause occurs.
• Serum Inhibin A is reported to be increased in about 70% of patients with granulosa cell tumors (stromal sex cord tumor). It may also be increased in a smaller percentage of patients with mucinous epithelial tumors (20%) but is less helpful in non-mucinous tumors. Most studies have been performed in menopausal women, where its utility is greater than in premenopausal women - this is because levels are normally higher and more variable in the latter group.

Clinical Utility

• Inhibin A may aid in the diagnosis of ovarian granulosa cell tumors particularly when used in combination with Inhibin B.
• If Inhibin A was elevated at the time of granulosa cell tumor or mucinous epithelial tumor diagnosis, Inhibin A may help in patient monitoring.

CPT Codes

86336
LOINC: 23883-2

Contacts

Last Updated

6/16/2021