621511 Medical Laboratories

Official definition

This U.S. industry comprises establishments known as medical laboratories primarily engaged in providing analytic or diagnostic services, including body fluid analysis, generally to the medical profession or to the patient on referral from a health practitioner.

Examples Census gives

• Blood analysis laboratories
• Medical pathology laboratories
• Medical bacteriological laboratories
• Medical testing laboratories
• Medical forensic laboratories

Source: US Census Bureau, 2022 NAICS descriptions.

When to use a different code

Census classifies these close-sounding activities somewhere else. Businesses mainly engaged in:

• Establishments known as dental laboratories primarily engaged in making dentures, artificial teeth, and orthodontic appliances to prescription are classified in U.S. Industry 339116, Dental Laboratories.
• Establishments known as optical laboratories primarily engaged in grinding lenses to prescription are classified in U.S. Industry 339115, Ophthalmic Goods Manufacturing.
• Establishments known as orthopedic laboratories primarily engaged in making orthopedic or prosthetic appliances to prescription are classified in U.S. Industry 339113, Surgical Appliance and Supplies Manufacturing.
• Establishments primarily engaged in providing health screening or physical fitness evaluation services (except by offices of health practitioners) are classified in U.S. Industry 621999, All Other Miscellaneous Ambulatory Health Care Services.

Source: US Census Bureau, 2022 NAICS cross-references.

Activities listed under 621511

The Census index assigns these 19 activities to this code. If your business matches one, this is your code.

• Bacteriological laboratories, diagnostic
• Bacteriological laboratories, medical
• Biological laboratories, diagnostic
• Blood analysis laboratories
• Cytology health laboratories
• DNA testing laboratories
• Forensic laboratories, medical
• Genetic testing laboratories
• Laboratories, medical (except radiological, X-ray)
• Laboratory testing services, medical (except radiological, X-ray)
• Medical laboratories (except radiological, X-ray)
• Medical pathology laboratories
• Mycology health laboratories
• Parasitology health laboratories
• Pathological analysis laboratories
• Pathology laboratories, medical
• Testing laboratories, medical
• Toxicology health laboratories
• Urinalysis laboratories

Source: US Census Bureau, 2022 NAICS index file.

SBA size standard for 621511

To count as a small business for SBA loans and federal contracts under NAICS 621511, your business (including affiliates) must not exceed $41.5 million in average annual receipts. Check your business.

Source: SBA table of size standards, effective March 17, 2023.

Closest UK SIC 2007 codes

There is no official one-to-one link between NAICS and UK SIC. These codes share the same international class (ISIC Rev. 4: 8690), so treat them as a starting point and check the definition.

• 86900Other human health activitiesUK SIC

Built from Census concordances 2022→2017 NAICS and 2017 NAICS→ISIC Rev. 4.

Similar codes to compare

• 621512Diagnostic Imaging Centers