Cardiotocography

Also known as CTG.

This is an investigation used in obstetrics.

Technique 

External CTG

One probe is placed above the fetal heart.
One probe is placed above the fundus.

Internal CTG

One probe is placed on the fetal scalp.

 

Metrics

1. Fetal heartbeat
2. Indicator showing movements felt by mother (caused by pressing a button)
3. Fetal movement
4. Uterine contractions

[Medical microbiology] Investigations

Medical microbiology homepage

• Blood culture - Adults
• Helicobacter pylori stool antigen test
• Sputum culture
• Stool culture
• Urine culture

[Haematology] Investigations

Haematology homepage

• Blood film
• Clotting Screen
• Crossmatch
• D-Dimer
• Erythrocyte Sedimentary Rate 
• Full blood count
• Group and Save

[Immunology] Investigations

Immunology homepage 

• Acetylcholine receptor antibody
• Cardiolipin antibodies
• Centromere antibody
• Citrullinated protein antibody
• Anti-GAD 
• Glomerular basement membrane antibody
• Intrinsic factor antibody
• Liver antibodies
• Anti-neutrophil cytoplasmic antibody
• Anti-NMDA receptor antibodies
• Anti-nuclear antibody
• Pancreatic islet cell antibodies
• Rheumatoid Factor
• Anti-tissue transglutaminase
• TSH Receptor antibody
• Voltage gated Ca2+ antibodies 

[Medical biochemistry] Investigations

Biochemistry homepage 

 

Blood

• Alpha fetoprotein   
• Amylase   
• C-peptide  
• C-Reactive protein (CRP)
• Cholesterol (total)
• Ferritin
• Folate
• Follicle stimulating hormone
• Growth hormone
• HbA1c
• Lithium
• Liver function tests
• Luteinizing hormone    
• Prostate Specific Antigen
• Thyroid function tests
• Total protein
• Triglyceride
• Tropinin T
• Tryptase
• Urea and Electrolytes
• Vitamin B1
• Vitamin B12

Faeces

• Faecal calprotectin
• Faecal elastase  
• Faecal occult blood
• Faecal porphyrins

Urine

• Bence Jones protein
• Urine cortisol 
• Urine drugs of abuse
• Urine osmolality 
• Urine porphyrin 
• Urine porphobilinogen
• Urine protein
• Urine steroid profile

Urine drugs of abuse

Biochemistry homepage  

  

Clinical indications:

Screen for recent use of drugs of abuse. Seven drugs of abuse are included in the screen, these are:

1. Amphetamines / MDMA
2. Benzodiazepines
3. Cannabis (THC)
4. Cocaine
5. Methadone metabolite (EDDP)
6. Opiates
7. Heroin metabolite (6-AM)

 

Specimen type: 

• Urine

 

Sample type: 

• Random Urine

 

Turnaround time: 

• Inpatient: 6 hours 
• Outpatient: 24 hours 
• GP: 24 hours

Urine steroid profile

Biochemistry homepage  

 

Clinical indications:

• Used for the identification of inborn errors of steroid metabolism. 
• Other uses include investigation of steroid metabolism in non-endocrine disease (e.g. liver disease) 
• Effects of drugs
• Herbal remedies 
• Illegal substances

 

Specimen type: 

• Urine

 

Sample type: 

• Random urine
• 24 Hour Urine

 

Turnaround time: 

• 2 - 3 weeks

Urine protein

Biochemistry homepage  

 

Clinical indications:

• Measurement of total protein in urine is important in the diagnosis and treatment of diseases associated with renal, cardiac and thyroid function.
• Increased levels of urine protein may also be present following strenuous exercise
• Monoclonal gammopathies 
• Urinary tract infections

 

Specimen type: 

• Urine

 

Sample type: 

• Random urine
• 24 Hour Urine

 

Turnaround time: 

• Inpatient: 6 hours 
• Outpatient: 24 hours
• GP: 24 hours 

 

Reference interval:

• 24 hour urine: 0.05 - 0.08g/24 hour (at rest) 
• Random urine: 0 - 50 mg/mmol creatinine

Urine osmolality

Biochemistry homepage 

 

Clinical indications:

• Determination of serum and urine osmolality can be useful in the assessment of electrolyte and acid-base disorders. 
• Comparison of serum and urine osmolalities can determine the status of renal water regulation in settings of severe electrolyte disturbances as might occur in diabetes insipidus or the syndrome of inappropriate anti-diuretic hormone. 
• Osmolality may also be performed as part of a water deprivation test (used in the diagnosis of diabetes insipidus) or where there is suspicion of ingestion of an osmotically active substance such as ethanol, methanol or ethylene glycol. 

 

Specimen type: 

• Urine

 

Sample type: 

• Random Urine

 

Turnaround time:

• Inpatient: 24 hours
• Outpatient: 24 hours
• GP: 24 hours

 

Reference interval:

300-900 mOsm/kg

Radiation dose from common radiological investigations

Medical specialty: Radiology

Many radiological investigations utilise ionising radiation. 
The average person in the USA receives an estimated effective dose of about 3 mSv per year from background (natural) radiation. Medical imaging can contribute greatly to the lifetime dose.

 

Radiological investigations

1. Ultrasound scan: No ionising radiation
2. MRI: No ionising radiation
3. fMRI: No ionising radiation
4. Bone Densitometry (DEXA): 0.001 mSv ionising radiation
5. X-ray of extremity (hand, foot, etc.): 0.01 mSv ionising radiation 
6. Dental X-ray: 0.01 mSv
7. Chest radiograph: 0.02 mSv 
8. Skull X-ray: 0.07 mSv
9. Cervical spine X-ray: 0.08 mSv
10. Fluoroscopy: 0.19 mSv
11. CT sinus: 0.2 mSv 
12. Hip X-ray: 0.3 mSv 
13. Mammography: 0.4 mSv
14. Abdominal X-ray: 0.7 mSv
15. Pelvic X-ray: 0.7 mSv
16. Thoracic spine X-ray: 0.7 mSv
17. Lumbar spine X-ray: 1.3 mSv
18. CT head: 2 mSv 
19. Intravenous pyelogram : 2.5 mSv
20. CT chest: 8 mSv
21. CT Abdomen/Pelvis : 10 mSv
22. CT pulmonary angiogram (CTPA): 10 mSv
23. Coronary Computed Tomography Angiography (CTA): 12 mSv
24. PET-CT (PET and CT): Up to 25 mSv

Blood film

Clinical indications:

Morphological assessment of the peripheral blood.
Used to assess many disorders including:

• Leukaemia 
• Anaemia
• Malaria

 

Profile:

• FBC added on the same sample

 

Specimen type: 

• Blood

 

Sample type: 

• EDTA

 

Turnaround time: 

• Urgent: 2 hours
• Routine: 3 days

Intravenous pyelogram

Radiology homepage 

Also known as IVP, intravenous urogram or IVU.

In IVP, the contrast agent is given intravenously, allowed to be cleared by the kidneys and excreted through the urinary tract as part of the urine.

Multiple X-ray images are created over time to show the transit of fluid through the urinary tract. This allows the kidneys, ureters and bladder (KUB) to be visualised.

Dose of ionising radiation: 2.5 mSv 

 

Contraindications

• Metformin use: If the patient requires <100mls of contrast or renal impairment is found before administration of the contrast, metformin should be stopped 48 hours before and after the procedure.
• Contrast allergy: If the patient has any previous history of adverse or moderate reactions to contrast media.
• Patient with significantly decreased renal function: Contrast media can be nephrotoxic and worsen renal function.

 

Compare with:

• Kidneys, ureters, and bladder x-ray (KUB) : does not use contrast agents

Anti-NMDA receptor antibodies

This is a test for an antibody (immunoglobulin) in the serum.

N-methyl-D-aspartate (NMDA) receptor antibodies are associated with the different sub units of the NMDA receptor.

 

Clinical indications:

• Antibodies to the delta or NR2 subunits of NMDAR are associated with limbic encephalitis, systemic lupus erythematosus (SLE), ataxia and epilepsia partialis continua. 
• Antibodies against the NR1, NR2A and NR2B subunits of the NMDAR are found in patients presenting with psychiatric symptoms, amnesia, seizures, dyskinesias, autonomic dysfunction and loss of consciousness. 
• Antibodies against the NR1 or NR2 subunits of the NMDAR: Anti-NMDA receptor encephalitis

 

Specimen type: 

Blood

Sample type: 

Serum (can be paired with CSF sample)

Turnaround time: 

3 weeks

 

Immunology homepage 

Anti-GAD

This is a test for an antibody (immunoglobulin) in the serum. This antibody binds to glutamic acid decarboxylase (anti-GAD).

 

Clinical indications:

• Insulin-dependent diabetes mellitus
• Stiff-person syndrome (60% sensitivity)

 

Specimen type: 

Blood

 

Sample type: 

Serum

 

Turnaround time: 

3 weeks

 

Immunology homepage

Voltage gated Ca2+ Antibodies

This is a test for a group of antibodies (immunoglobulin) in the serum. 

Clinical indications:

The assay is positive in

• Approximately 85% of patients with Lambert Eaton myasthenic syndrome (with or without SCLC)
• About 30% of Cerebellar ataxia with SCLC
• In a few cases with small cell lung cancer without myasthenic symptoms (in low titre). This is because small cell lung cancers express this voltage gated calcium channel.

Specimen type: 

Blood

 

Sample type: 

Serum

 

Turnaround time: 

4 weeks

 

Immunology homepage 

Cardiolipin Antibodies

This is a test for two types of antibody (immunoglobulin) in the serum. IgG and IgM.

 

Clinical indications:

Recommended testing for anti-phospholipid syndrome. Testing must also include Lupus anticoagulant. Beta 2 glycoprotein 1 testing is also recommended

 

Profile:

Lupus anticoagulant, thrombophilia testing and Antiphospoholipid syndrome investigation includes ACA, ACAM.

 

Specimen type: 

Blood

 

Sample type: 

Serum (+ 2x citrate for Lupus anticoagulant)

 

Turnaround time: 

7 Days

 

Immunology homepage 

[Vascular surgery] Procedures

Introduction to vascular surgery

Procedures

 

Investigations

• Intravascular ultrasound
• Carotid ultrasonography
• Carotid duplex
• Digital subtraction angiography
• Cerebral angiography
• Venography
• Impedance phlebography

Removal of foreign bodies

• Vascular snare

Aneurysm repair

• Endovascular aneurysm repair (EVAR)
• Open surgery

Revascularisation

• Thrombectomy 
• Angioplasty
• Percutaneous transluminal angioplasty (PTA)
• Stenting
• Endarterectomy
• Carotid artery
• Femoral artery 
• Laser endarterectomy
• Atherectomy 
• Vascular bypass
• Femoral popliteral bypass surgery

Chronic venous disease

• Vein stripping
• Ambulatory phlebectomy
• Sclerotherapy
• Laser ablation

Endovascular surgery vs open surgery

Endovascular procedures are superior to open surgical procedures in several ways: the risk of infection is lower, the trauma inflicted to the overlying tissues is minimal. Studies have shown that in the short-term, endovascular repair of abdominal aortic aneurysm confers signficantly better patient mortality than open surgical repair.

However, endovascular surgery is a younger field than open surgery, and there are several trade-offs, including reduced visibility. Long-term patient mortality is significantly better in patients treated with open surgical repair, than in patients treated with endovascular repair. The increased mortality associated with endovascular repair is largely attributable to secondary aneurysm sac rupture.

[Urology] Procedures

General urinary tract investigations

• Radiograph: Kidneys, Ureters, and Bladder (KUB)
• Intravenous pyelogram
• CT urography

Bladder

• Cystoscopy
• Suprapubic cystostomy

Prostate

• Transurethral resection of the prostate
• Prostate biopsy 

Vas deferens

• Vasectomy 
• Vasovasostomy (vas deferens to vas deferens) 
• Vasoepididymostomy (epididymis to vas deferens connection)

Urethra

• Urinary catheterisation
• Retrograde urethrogram
• Urethrotomy
• Urethroplasty
• Urethral bulking injections (gynaecology)

Penis

• Penile plethysmography (PPG)
• Penile prosthesis
• Penectomy

Foreskin and frenulum

• Preputioplasty
• Superincision
• Circumcision
• Frenuloplasty of prepuce of penis

Testicles 

• Orchiopexy
• Orchidectomy (Gonadectomy)

Electrocardiogram

Also known as an ECG or EKG.

 

Indications

• Suspected cardiac arrhythmia

Faecal Occult Blood

Biochemistry homepage  

 

This is a test to find invisible traces of blood in the faeces.

 

Clinical indications:

• Suspicion of bleeding in the gastrointestinal tract

 

Specimen type: 

• Faeces

 

Sample type: 

• Faeces

 

Turnaround time: 

• 1 week