Serotonin
Other names: 5-HT; 5-Hydroxy Tryptamine
Serotonin is a chemical, which is produced from the amino acid tryptophan; it helps to regulate the constriction of blood vessels, transmit nerve impulses and controls moods. 90 percent of the serotonin in the blood is found in the platelets; it is produced when it is needed by the brain and other cells in the bronchial tubes and gastrointestinal tract. Serotonin is metabolised by the liver; the resulting metabolites are excreted in the urine.
When is the test used?
The test is used primarily to detect carcinoid tumours; the test is usually ordered if the patient has already had a 24 hour urine 5-HIAA test. The test is usually ordered when the patient has symptoms associated with carcinoid tumours.
How is the test done?
The test is done by collecting and analysing a sample of the patient’s blood; in most cases, a syringe is inserted into a vein on the inside of the elbow and the blood is drawn out using a syringe. When the doctor or nurse has a sufficient sample, the blood will be bottled, branded with the patient’s name and sent off to the laboratory for analysis.
What do the test results mean?
If levels of serotonin are higher than normal and the patient has symptoms of a carcinoid tumour, this indicates it is likely that the patient has a tumour; however, the result will not be sufficient to form a diagnosis and further tests, including scans and biopsies, will be ordered.
If levels of serotonin are normal and the patient does not have symptoms of a carcinoid tumour, it is unlikely that they have a tumour.
If levels of serotonin are normal but the patient has symptoms of a tumour, this may still indicate that they have a tumour and further tests will be required; some tumours do not produce serotonin.
Specific Blood Tests
- Specific Blood Tests
- Factor V Leiden Mutation and PT 20210 Mutation
- Ferritin Test
- Fibrinogen
- Fructosamine
- FSH Test
- G6PD
- Gastrin
- GGT
- Glucose test
- Growth hormone
- Haemoglobin
- Haptoglobin
- HbA1c test
- HDL Cholesterol Test
- Helicobacter Pylori test
- Heparin Anti-Xa
- Hepatitis A Virus
- Hepatitis B Virus
- Hepatitis C Virus
- Her-2/neu Testing
- Heterophil Antibody Titre
- High-Sensitivity C-Reactive Protein
- HIV Antibody Test
- HIV Resistance Testing
- HIV Viral Load
- IGF-1
- Immunoreactive Trypsin
- Insulin
- Iron test
- LDH
- LDL Cholesterol Test
- Lead Test
- LH Test
- Lipase Test
- Lipoprotein (a)
- Lithium
- Lupus Anticoagulant
- Lyme disease test
- Maternal screening
- Mercury, Urine and Blood
- Mycophenolic Acid
- Myoglobin Test
- Oestrogen
- Osmolality
- Overdose Drug Test
- Paracetamol
- Parathyroid Hormone
- Parvovirus B19
- PCV
- Pertussis
- Phenobarbital
- Phenytoin
- Phospate
- Platelet Count
- Porphyrins
- Potassium Test
- Prealbumin Test
- Procalcitonin
- Progesterone Test
- Prolactin
- Prostate-Specific Antigen
- Protein 24 Capsid Antigen
- Protein C and Protein S
- Protein Electrophoresis Immunofixation Electrophoresis
- Prothrombin Time
- PSEN1 Test
- PTH
- Reticulocyte count
- Rheumatoid factor
- Rubella test
- Salicylic Acid
- Serotonin
- Sex Hormone Binding Globulin
- Sickle Cell Test
- Sirolimus
- Smooth Muscle Antibody
- Sodium Test
- Soluble Mesothelin-Related Peptides
- Synacthen Test
- Syphilis Test
- Tacrolimus
- Tau protein
- Testosterone Test
- Theophylline & Caffeine
- Thiopurine s-methyltransferase
- Thyroglobulin (Tg)
- Thyroid peroxidase antibody (TPOAb)
- Thyroid-Stimulating Hormone
- Thyroxine
- TIBC, UIBC & Transferring
- TORCH Test
- Total Protein test
- Triiodothyronine
- Triglycerides Test
- Troponin test
- Urea test
- Uric Acid
- Valproic Acid
- Vancomycin
- Very Low Density Lipoprotein
- Vitamin B12 and Folate
- Vitamin D
- West Nile Virus
- White blood cell differential count
- Zinc Protoporphyrin
- Activated Clotting Time
- ACTH
- Albumin
- Aldosterone and Renin
- Alkaline Phosphatase Test
- Allergen-Specific IgE Antibody Test
- Alpha-1 Antitrypsin
- Alpha-Fetoprotein
- ALT
- AMA
- Ammonia
- Amylase Test
- Angiotensin Converting Enzyme
- Antinuclear Antibody
- Antithrombin
- Apolipoprotein A-I
- Apolipoprotein E Genotyping
- aPTT
- AST
- Bicarbonate
- Bilirubin
- Blood cultures
- Blood film
- Blood Gas Tests
- Blood Ketones
- Brain Natriuretic Peptide
- BRCA-1 & BRCA-2
- CA 125
- Cancer Antigen 15-3
- Cancer Antigen 19-9
- C-peptide
- Caeruloplasmin
- Calcitonin
- Calcium Test
- Carbamazepine
- Cardiac Risk Assessment
- Cardiolipin Antobodies
- Catecholamines, Plasma and Urine
- CCP
- CD4 and CD8
- CEA Test
- CF Gene Mutation Testing
- Chickenpox and Shingles Tests
- Chloride Test
- Cholesterol Test
- Chlorinesterase Test
- Chromogranin A
- Ciclosporin
- CMV
- Coagulation Factors
- Coeliac Disease Tests
- Copper
- Cortisol Test
- Creatine Kinase CK-MB Test
- Creatine Kinase Test
- Creatinine
- Creatinine Clearance
- C-Reactive Protein
- Cystatin C
- D-Dimer
- DHEAS
- Digoxin
- Direct LDL cholesterol
- eGFR - Calc. Creatinine Clearance
- Electrolytes
- Epstein-Barr Virus Antibodies
- Erythrocyte Sedimentation Rate
- Erythropoietin
- Ethanol
Blood Test Guide
- Blood Tests
- Types of blood tests
- what to expect
- What are the risks of blood tests?
- What do blood tests show?
- Specific Blood Tests