SERUM AMYLASE TEST

Measurement of serum or plasma amylase activity is usually requested to assist in the differentiation of acute pancreatitis from other acute abdominal disorders. It is an early indicator of acute pancreatitis.

What are the Normal ranges for Serum amylase test?

70-340 U/l

What causes high levels of serum amylase?

Acute pancreatitis
Very high concentrations of serum or plasma amylase (over 1850 U/l) are virtually diagnostic of acute pancreatitis or acute episodes of chronic relapsing
pancreatitis. Read more.

Other conditions giving raised amylase values
Serum or plasma amylase levels of approximately 740–1500 U/l may be due to:
– Renal failure
– Salivary gland obstruction or inflammation such as
with mumps
– Diabetic ketoacidosis
– Opiate drugs and some antiretroviral drugs
– Alcoholism
– Hypothermia
– Ectopic pregnancy
– Almost any acute abdominal emergency, and also cholecystitis, perforated peptic ulcer, or peritonitis.

Falsely raised amylase level
Falsely elevated amylase levels may result if the serum is markedly turbid or the sample has been contaminated with amylase during analysis.

SERUM ALANINE AMINOTRANSFERASE(ALT) TEST

Also referred to as to Glutamate Pyruvate Transaminase (GPT)

Measurement of ALT activity is mainly performed to investigate liver disease. Increasingly ALT is being measured to monitor patients receiving antiretroviral drugs associated with hepatotoxicity such
as nevirapine (NVP) and stavudine (d47).

While both ALT and AST are raised with hepatocellular injury, ALT is more specific for detecting liver cell damage.

What are the Normal ranges for Serum ALT ?

5–35 IU/l

Causes of high levels of serum ALT

Liver disease
The most important cause of raised ALT activity is hepatocellular injury. With acute hepatocellular injury, AST levels are usually higher than ALT levels. As damage continues, ALT activity becomes higher. In viral hepatitis, both enzymes are usually raised before the patient becomes jaundiced.

In Liver cirrhosis:
ALT levels fall below AST levels. Both ALT and AST are raised in hepatitis caused by hepatotoxic antiretroviral drugs.

Obstructive liver disease is usually accompanied by only small or moderate ALT and AST rises especially in the early stages. With complete obstruction, enzyme levels fall.

ALT and AST enzymes are artefactually increased when haemolysis is present or if the blood has been stored without separation of the serum or
plasma.

SERUM ASPARTATE AMINOTRANSFERASE TEST (AST)

What causes increase in Serum ALT?

It also referred to as Glutamate Oxaloacetate Transaminase (GOT)

Myocardial infarction
An important cause of elevated AST activity is myocardial infarction, i.e. destruction of an area of heart muscle because its blood supply has been cut off due to a blood clot in a coronary artery. The enzyme level rises soon after the coronary vessel becomes blocked, reaches its highest value 24–48 hours after the infarct and returns to normal usually within 3–5 days. In general, the more extensive the infarct, the higher the AST peak level.

Other causes of raised AST levels
Because AST is widely distributed in body tissues, many other diseases involving cellular injury may be accompanied by increases in AST levels:
– Severe bacterial infections, – -Malaria,pneumonia
– Infectious mononucleosis, Pulmonary infarcts, and tumours.
AST activity is also increased in some muscle disorders and following surgery, injury or blood transfusion.

ALT and AST enzymes are artefactually increased when haemolysis is present or if the blood
has been stored without separation of the serum or
plasma.

SERUM ALBUMIN TEST

Serum albumin is mainly measured to investigate liver diseases, protein energy malnutrition, disorders of water balance, nephrotic syndrome, and protein-losing gastrointestinal diseases.

What are the Normal ranges for Serum albumin Test?

30 – 40g/dl

What does test result mean?

Increases Serum albumin levels are rarely raised except in
diarrhoea or prolonged vomiting and artefactually by prolonged venous stasis.

Decreases
Hypoalbuminaemia occurs whenever there is increased plasma volume (e.g. in pregnancy).
Pathological causes include:
– Low protein intake as in protein energy malnutrition.
– Malabsorption as in chronic pancreatitis, coeliac disease, and sprue.

See also:

SERUM BILIRUBIN TEST

The measurement of serum or plasma bilirubin is usually performed to investigate the causes of liver disease and jaundice, and to monitor a patient’s progress, e.g. an infant with serious neonatal jaundice (high levels of unconjugated bilirubin).

Bilirubin is a product of erythrocytes breakdown and exists as conjugated or non- conjugated. These two combined gives the Total Bilirubin.

What are normal ranges for Total bilirubin?

Adults: 3–21 mol/l 0.2–1.3 mg/100 ml

Newborns: 8–67 mol/l 0.5–4.0 mg/100 ml

What does high serum Bilirubin indicate?

RISE in the level of bilirubin in the blood is called hyperbilirubinaemia. The main causes are as follows:

● Overproduction of bilirubin caused by an excessive breakdown of red cells (haemolytic jaundice). The bilirubin is of the unconjugated type.
In tropical countries haemolysis is due mainly to:
– Severe falciparum malaria.
– Sickle cell disease haemolytic crisis.
– Haemolysis associated with glucose-6-
phosphate dehydrogenase deficiency and
hereditary spherocytosis.
– Antigen antibody reactions as in haemolytic disease of the newborn, autoimmune haemolytic anaemias, or following an incompatible blood transfusion.
– Toxins from bacteria, snake venoms, drugs or herbs.

● Liver cell damage in which there is usually an increase in both conjugated and unconjugated bilirubin (hepatocellular jaundice). The commonest causes are:
– Hepatitis caused by hepatitis viruses and other viruses
– Leptospirosis
– Relapsing fever
– Brucellosis
– Typhoid
– Chemicals, plant toxins and drugs

● Metabolic disturbances in the liver involving defective conjugation, transport and, or, excretion
of bilirubin. Examples include:
– type of neonatal jaundice, often referred to as ‘ physiological jaundice’
– Rare inherited disorders of conjugation such as Gilbert’s and Crigler-Najjar syndromes.

● Partial or complete stoppage of the flow of bile through bile channels with a build up of conjugated bilirubin in the blood (obstructive
jaundice). Cholestasis can be due to:
– Obstruction of the extra-hepatic biliary ducts by gallstones, tumours (especially hepatomas and carcinoma of the pancreas), cholangitis
(inflammation of the biliary ducts), or by
helminths such as Opisthorchis and Fasciola species. Occasionally heavy Ascaris infections, especially in children, may result in blockage of the common bile duct.
– Pressure on the small bile ducts as may occur in hepatitis or as a side effect of drugs.

NB: Mild to moderate hyperbilirubinaemia may also be found in association with any serious condition such as a terminal illness, or following major trauma, surgery, or blood transfusion

MEGALOBLASTIC ANEMIA

  • Hypersegmented nuclei
  • Macroovalocytes
  • Erythroid hyperplasia in bone marrow
  • Giant metamyelocytes
  • Hight bilirubin and Lactate dehydrogenase
  • Presence of Howell jolly bodies
  • Anisopoikilocytosis
  • Lack of polychromasia
  • High MCV
  • Pancytopenia

Clinical Features

  • Evidence of ineffective erythropoiesis
  • Neuropathy
  • Cognitive impairment
  • Loss of position
  • Atrophic glossitis

SKIN SCRAPING FOR FUNGAL DETECTION


• Clean skin with 70% alcohol.

• Scrape edges of lesion (as edge has greatest amount of viable fungus) with a blunt scalpel blade.

• Collect skin scales in a sterile petri dish or similar wide-mouthed container or alternatively, skin scrapings may be collected in a clean, dry piece of paper folded securely with Scotch tape and labelled properly.

• If a skin scraping does not yield sufficient material, then a swab or Scotch tape could be pressed on the lesion

See also:

NAIL SAMPLE FOR FUNGAL DETECTION


• Clean nail with 70% alcohol.

• Examine for damaged, discoloured, brittle or dystrophic area.

• Material should be taken from the affected areas.

• Entire thickness of the damaged nail should be cut as far back as possible. Any crumbly material or material under the nail should be collected and sent in a sterile container.

• If skin lesions are present they should be scraped and the material collected should be sent separately.

See also:

EYE SWAB AND SCRAPING FOR FUNGAL DETECTION


• Pus and discharge samples can be collected with a cotton wool swab and sent using standard precautions to the lab.

• Due to the sensitivity of the region and serious consequences of error, only an experienced ophthalmologist collects eye samples (e.g. corneal scrapings, intraocular fluid aspirate and swabs).

• For corneal scrapings, inoculate media plates and prepare slides at the patient’s side. Always contact the laboratory to obtain suitable media prior to the procedure. Alternatively, send corneal scrapings directly to the laboratory.

• Intraocular fluid (vitreous and aqueous) is collected using specialised equipment in the operating room.

• If sample is insufficient to perform both smear and inoculation of plates, give priority to culture.

• In case of contact lens-related infections, send contact lenses, case and cleaning solution to the lab for culture as well. Ear Swab and Scraping

• A physician collects samples from outer and middle ear. Skin scrapings from the external auditory canal are preferred. Use a sterile swab stick to collect exudates or debris.

• For deeper ear infections and to avoid damage to the ear drum, an ENT surgeon or experienced physician should use a speculum to draw specimen.

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SPUTUM, TRACHEAL ASPIRATE & LAVAGE FOR FUNGAL DETECTION

Sputum

• Patient submits the first morning expectorated sample (optimal) with the following instructions:

• Clean mouth with several rinses of sterile saline or water.

• Cough out 2-5 ml of sputum (not saliva) in a wide-mouthed sterile container.

• In case of dry cough, perform sputum induction with hypertonic saline nebulisation.

• Acceptability of sputum is determined with a Gram stained smear (pus cells >25/LPF, epithelial cells and only representative samples are accepted.

• 24-hour sputum collections are not acceptable.

Tracheal Aspirate

• Tracheal aspirates are collected through an endotracheal tube and are subject to the same limitations as sputum specimens.

Non-Directed Bronchoalveolar Lavage

• This method provides a lower respiratory tract sample without the need for bronchoscopy.

• A trained physician passes a suction catheter down the endotracheal tube until resistance is met.

• Inject an aliquot of sterile saline and then aspirate at least 1 ml of secretions.

• Non-directed techniques have been found to give results comparable to bronchoscopic methods.

See also: