What time is specified by concept 58645-3 ?

Regarding to a concept 58645-3 Cortisol [Moles/​volume] in Saliva (oral fluid) --12 PM specimen, the Chinese language variant showed “

皮质醇^晚上12点标本” which indicates midnight cortisol. However, in the related names there is a “Noon” which implied the test is noon cortisol?

May I know what time is actually specified by this concept in case I want to provide LOINC code for cortisol with late-night sample?

Thank you very much!

Best Regards,


Health Informatics

Hong Kong Hospital Authority


I can affirm in English this concept is intended to be 12 noon (mid day). I will leave it up to the translators to investigate the Chinese language variant.

If you should need the midnight saliva Cortisol measurement, the LOINC code is 58643-8

Best regards,


Dear Pam,

Thank you very much! By the way, the situation is quite funny. Some people counting time like this:

  1. 4AM=morning, before sunrise.
  2. 8AM=morning, breakfast time.
  3. 12AM=noon, lunch time.
  4. 4PM=afternoon, before sunset.
  5. 8PM=evening, dinner time.
  6. 12PM=midnight.

    I am thinking whether 12 AM or 12 PM to indicate midnight and noon is a bit confusing? Will LOINC consider to apply ISO8601 24-hour-clock standard in either the LOINC common name or related name, to clear off uncertainty?

    Thank you again.

    Best Regards,

    Wai Kin CHEUNG

    Health Informatics

    Hong Kong Hospital Authority

Interesting comments. In Canada we use the 24 hour clock as our standard for these tests and it does eliminate any confusion. For the tests listed we provide:

58645-3 Cortisol 1200h

58643-8 Cortisol 2400h

I agree that incorporating the 24 hour clock into the Long Common Name makes sense, so revised names would appear as:

58645-3 Cortisol [Moles/volume] in Saliva (oral fluid) --1200h specimen

58643-8 Cortisol [Moles/volume] in Saliva (oral fluid) --2400h specimen


Lorie Carey

Standards SME

Canada Health Infoway