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Abnormal Blood Tests - How to prevent?

Abnormal Blood Tests - Causes and Risk Factors

1. Raised Tumour Markers
a. Alpha-fetoprotein (AFP)

In conjunction with abdominal ultrasonography, it is recommended that alphafetoprotein (AFP) be measured at six-monthly intervals in patients at high risk for hepatocellular carcinoma (especially those with liver cirrhosis related to hepatitis B or hepatitis C). A raised AFP is found in 80% of patients with hepatocellular carcinoma and in 40% of these patients, the AFP exceeds 1000 ng/mL.

However, AFP can be raised in other cancers, namely:

  • Non-seminomatous germ cell tumours
  • Gastric cancer
  • Biliary tract cancer
  • Pancreatic cancer
  • Lung cancer

AFP can be raised in non-malignant conditions like:

  • Cirrhosis
  • Viral hepatitis
  • Ataxia telangiectasia
  • Pregnancy
b. Carcinoembryonic Antigen (CEA)

Carcinoembryonic antigen (CEA) is a glycoprotein, which is present in normal mucosal cells but increased amounts are associated with adenocarcinoma, especially colorectal cancer. Levels exceeding 10 ug/L are rarely due to benign disease. Sensitivity increases with advancing colorectal cancer state. However, poorly differentiated tumours are less likely to produce CEA.

CEA levels are useful in assessing prognosis (with other factors), detecting recurrence and monitoring treatment in patients with colorectal cancer.

Conditions which may have elevated CEA include:

  • Colorectal cancer; tumours on the right side of the colon tend to produce higher CEA levels than tumours on the left side
  • Breast cancer
  • Lung cancer
  • Gastric cancer, oesophageal cancer, pancreatic cancer
  • Mesothelioma
  • Skeletal metastases
  • Non-malignant liver disease, including cirrhosis, chronic active hepatitis
  • Chronic kidney disease
  • Pancreatic disease
  • Inflammatory bowel disease, diverticulitis, irritable bowel syndrome
  • Respiratory diseases, eg. pleural inflammation, pneumonia
  • Smoking
  • Ageing
  • Atherosclerosis
c. Carbohydrate Antigen 19-9

Elevated levels of CA19-9, an intracellular adhesion molecule, occur primarily in patients with pancreatic and biliary tract cancers, but may be raised in colorectal, gastric, hepatocellular, oesophageal and ovarian cancers.

Benign conditions such as cirrhosis, cholestasis, cholangitis and pancreatitis also result in elevations, although values are usually less than 1000 u/mL. CA19-9 may be raised in diabetes mellitus.

2. Anaemia

Another abnormal blood test result that requires further evaluation and treatment is anaemia. For men, anaemia is typically defined as a haemoglobin level of less than 13.5g/dL and in women as haemoglobin of less than 12g/ dL. Some patients with anaemia have no symptoms but can be symptomatic if the haemoglobin is significantly low.

Anaemia can be categorized as microcytic (MCV less than 80FL), normocytic (MCV 80-100FL) or macrocytic (MCV more than 100FL). The most common cause of microcytic anaemia is iron deficiency anaemia, although hereditary disorders like alpha thalassaemia or beta thalassaemia needs to be excluded.

The most common causes of iron deficiency anaemia are:

  • A lack of iron in the diet of vegans and vegetarians
  • Heavy menstruation
  • Pregnancy
  • Rapid childhood growth
  • Peptic ulcer disease (H. pylori, NSAIDs)
  • Gastrointestinal malignancy (colorectal, gastric and small intestinal)
  • Coeliac disease
  • Crohn’s disease
  • Colonic polyps
  • Haemorrhoids Macrocytic anaemia may be caused by Vitamin B12 deficiency

Vitamin B12 deficiency may be due to:

  • Pernicious anaemia
  • Strict vegetarianism
  • Long-term alcoholism
  • Intestinal strictures (Crohn’s disease), blind loop syndrome and bacterial overgrowth (postsurgery)
3. Abnormal Liver Function Tests

Patients with no or minimal symptoms and abnormal liver function test results are common. These abnormal liver function tests fall in three main groups:

i. Isolated hyperbilirubinemia

ii. Predominantly raised serum alkaline phosphatase (SAP) and gamma-GT

iii. Predominantly raised alanine transaminase (ALT) and Aspartate transaminase (AST)

i. Causes of isolated hyperbilirubinemia include:
  • Hemolysis
  • Drugs
  • Gilbert’s syndrome, Crigler- Najjar syndrome, Dubin-Johnson syndrome
  • Chronic liver disease
ii. Causes of raised serum alkaline phosphatase (SAP) and gamma-GT (Cholestasis) include:
  • Primary biliary cirrhosis
  • Drugs (tricyclic antidepressants, erythromycin, oral contraceptive pill, anabolic steroids)
  • Primary sclerosing cholangitis
  • Cardiac failure
  • Space-occupying hepatic lesion (hepatoma or secondaries)
  • Head of pancreas neoplasm
  • Biliary malignancy
iii. Predominately raised ALT/AST (‘Hepatitic picture’) include:
  • Non-alcoholic steatohepatitis (NASH)
  • Alcoholic hepatitis
  • Cirrhosis
  • Medication (Statins, Isoniazid, Phenytoin, Paracetamol overdose)
  • Chronic hepatitis B, C
  • Autoimmune hepatitis
  • Acute hepatitis A, B, C, EBV and CMV infection
  • Metabolic-Glycogen Storage disorders, Wilson’s disease

Abnormal Blood Tests - Diagnosis

Abnormal Blood Tests - Preparing for surgery

Abnormal Blood Tests - Post-surgery care

Abnormal Blood Tests - Other Information

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth