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USEFULNESS OF THE BLOOD TESTS IN THE DIAGNOSIS OF GASTROINTESTINAL DISEASES IN PRIVATE PRACTICE

O P Kapoor

Ex. Hon. Visiting Physician, Jaslok Hospital and Bombay Hospital, Mumbai,
Ex. Hon. Prof. of Medicine, Grant Medical College and JJ Hospital, Mumbai 400 008.


Most of the practitioners will think of X-rays and imaging like sonography, CT scan and invasive investigations like endoscopy, etc. to diagnose abdominal conditions.

I am writing this article to draw the attention of the G.Ps that in the modern days we can make the diagnosis of a lot of abdominal diseases by blood tests. In the past stool was the only pathological investigation which was asked for. This test is losing its importance day by day. Following are the examples of the blood tests :

a. Diagnosis of peptic ulcer - blood tests for H-pyloridis antibodies for IgM and IgA are available in many of the pathological laboratories. These are fairly accurate to diagnose the presence of peptic ulcer in the stomach because of the close association which has been demonstrated between the ulcer and H-pyloridis.

b. In patients who go on getting recurrent gastric ulcers, duodenal ulcers, in the past physicians and surgeons asked for extensive investigations like CT scan of the pancreas etc. to rule out Zollinger Ellison syndrome. Inspite of all this they missed the diagnosis even at laparotomy because either the tumour was very very small or it was hyperplasia of the cells which was causing hyperacidity and then recurrent ulcers.

Now we have the blood test of serum gastrin available in the pathological laboratories who use radio immune assay machine. This test is strongly diagnostic of the above condition and such patients could be immediately put on large doses of Omeprazole which are to be taken more or less permanently (without any surgical interference.)

c. Abdominal parasites : So often abdominal parasites are not seen in the stools and yet they are present in the bowel. Blood tests can pick up these patients. A very good example is of anti-giardia IgM antibodies in the blood and antibodies against strongyloidis (infection which is likely to increase with the increased incidence of AIDS in future).

d. Amoebic liver abscess : If no imaging is available for any reason, if the blood tests show a positive IHA (indirect haemagglutination) test for amoebiasis combined with elevated serum alkaline phosphatase (stable fraction) and possibly leucocytosis - these are diagnostic of the presence of an amoebic abscess in the liver.

e. Diagnosis of acute pancreatitis : In the absence of all imaging procedures, markedly elevated serum amylase (more than 1000 units) which falls rapidly on the next day, is diagnostic of acute pancreatitis. Readings of markedly raised serum lipase with normal amylase in a patient of severe abdominal pain will be diagnostic of acute pancreatitis (in patients having hypertriglyceridaemia).

f. Diagnosis of tuberculous abdomen : In absence of all imaging facilities, a markedly raised ESR (around 100 mm), presence of AFB IgM antibodies is very much suggestive of extra pulmonary tuberculosis and in a patient of abdominal pain or diarrhoea diagnostic of abdominal tuberculosis. Now we have a very accurate blood test known as transcription mediated amplification (TMA) test which is as good as detecting RNA tubercle bacilli and is much more superior with less false positive as compared to tuberculous antibodies test which is highly deceptive.

g. Finally, presence of blood test for CEA (chorionic embryonic antigen) is diagnostic of malignancy in the small intestines. Similarly presence of high levels of alpha feto protein is diagnostic of a malignant tumour of the liver.



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