serum
serum — noun
1. The clear, pale-yellow liquid part of blood that stays after the blood clots and
The clear, pale-yellow liquid part of blood that stays after the blood clots and all the solid cells and clotting agents are taken out.
The lab technician separated the serum from the blood sample for further testing.
passive: separated from blood for analysis
Doctors check the level of vitamin D in a patient's blood serum to diagnose deficiencies.
check level of [substance] in blood serum
After the clot formed, only the clear serum remained at the top.
The hospital stored the serum samples in a refrigerated cabinet to keep them stable.
A small amount of serum was drawn from Maja's blood to check for food allergies.
- plasma
plasma is the liquid part of blood before clotting factors are removed; serum is plasma without those factors.
文法句型
serum of [blood/sample]
in/from the serum
用法筆記
Often used in expressions that describe medical tests measuring the amount of a substance in the blood, such as 'serum iron' or 'serum cholesterol'.
常見錯誤
2. A medical preparation taken from an immunised animal or person whose body has bu
A medical preparation taken from an immunised animal or person whose body has built protection against a disease, given to someone else to help them fight that disease or a poison.
After the snake bit his leg, the hospital gave Brian a dose of antivenom serum.
serum against poison (antivenom)
Doctors injected the patient with a serum to stop the infection from spreading further.
passive: injected with a serum
Scientists in the laboratory developed a new serum to fight the emerging virus.
Hamza received a serum that contained antibodies against the bacterial infection.
文法句型
serum against [disease/poison]
inject/give [someone] a serum
用法筆記
Differs from a vaccine: a serum contains ready-made antibodies from another person or animal, while a vaccine stimulates your own body to make antibodies.
常見錯誤
3. A thick liquid cosmetic product that packs a high amount of active ingredients a
A thick liquid cosmetic product that packs a high amount of active ingredients and aims to boost the quality or appearance of the skin or hair.
Mizuki applies a vitamin C serum to her face every morning before putting on cream.
apply [type] serum to [body part]
This hair serum repairs split ends and adds shine without making hair greasy.
hair serum — specific product category
The sales assistant recommended a hydrating serum for dry and tired-looking skin.
A few drops of the serum were enough to cover her whole face.
Ritu bought a serum with hyaluronic acid to help keep her skin soft during winter.
- essence
in skincare, 'essence' is typically lighter and more watery than a serum; serums are more concentrated.
- concentrate
a marketing term that overlaps with serum but can also refer to thicker treatments.
文法句型
[adjective] serum
apply serum to [area]
serum for [hair/skin]
用法筆記
Beauty serums are more concentrated than regular moisturisers or lotions. They are usually sold in small bottles with a dropper and applied in small amounts.
常見錯誤
4. A thin, watery liquid produced naturally in certain body tissues, such as the cl
A thin, watery liquid produced naturally in certain body tissues, such as the clear fluid that fills a skin blister or lubricates the space around internal organs.
The blister on Esme's heel was filled with clear serum that protected the new skin.
serum filling a blister
Serum collected around the surgical wound during the healing process.
The doctor explained that the swelling was caused by serum building up in the tissue.
Jabari noticed a watery serum leaking from the small cut on his finger.
- serous fluid
the more technical medical term; 'serum' in this sense is a shorter form used in clinical settings.
- lymph
lymph is a similar fluid but circulates through the lymphatic system; serum in tissues is not part of that system.
文法句型
serum in [body part/tissue]
用法筆記
In medical contexts this overlaps with 'serous fluid'. It is thinner than pus and does not contain the same infection-fighting white blood cells.
serum — adjective
1. Existing in, found in, or related to the clear, pale-yellow liquid part of the b
Existing in, found in, or related to the clear, pale-yellow liquid part of the blood that remains after clotting.
The test measures the serum cholesterol level to assess the risk of heart disease.
collocation: serum cholesterol level
Abnormal serum protein levels can be a sign of certain immune system disorders.
collocation: serum protein levels
Doctors monitor serum potassium carefully in patients with kidney problems.
A serum sodium test showed that Pim was mildly dehydrated after the long run.
- blood-serum
the hyphenated form is rarely used; 'serum' alone as an attributive adjective is the standard form.
文法句型
serum + noun (serum protein / serum level / serum test)
用法筆記
This adjective is only used before a noun. It appears mostly in medical reports and laboratory contexts, paired with words like 'level', 'concentration', 'protein', and 'test'.