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Lab Tests

Stool specimen

  • A stool specimen might be tested if a specialist wants to rule out bacterial or parasitic causes which can resemble IBD
  • Having IBD also makes you more susceptible to certain bacterial infections in the stool
  • Faecal calprotectin is a useful test for inflammation with the gut

Blood tests

  • Blood tests are among the most common of clinical investigations.
  • They are used to track general health, examine markers associated with disease activity, detect for nutritional deficiencies, and to monitor the efficacy and toxicity of medications
  • Blood tests cannot provide sole and conclusive evidence for a diagnosis of IBD; however specific markers provide useful information relevant to pathology
  • Results, expressed numerically, are compared against a reference range or the values seen in 95% of the population

Summary of typically tested elements in blood

White blood cell count

Other Names

WBC

Function

White blood cells travel in the bloodstream to areas of infection and destroy the responsible bacteria.

Normal Levels

3.3-8.7 K/uL

Blood Levels Associated With Active Disease

ELEVATED

What This Means

There is inflammation in the body.

Red blood cell count

Other Names

RBC

Function

Red blood cells carry oxygen to and remove waste products from the body's tissues.

Normal Levels

3.93-5.69 M/uL

Blood Levels Associated With Active Disease

LOWERED

What This Means

Not a major focus when assessing Crohn's disease or ulcerative colitis.

Haemoglobin

Other Names

HGB

Function

Haemoglobin is a protein inside red blood cells that carries oxygen

Normal Levels

12.6-16.1 g/dL

Blood Levels Associated With Active Disease

LOWERED

What This Means

Indicates anemia (some causes include malnutrition, blood loss).

Hematocrit

Other Names

HCT

Function

The hematocrit is the proportion of the blood that consists of red blood cells.

Normal Levels

38-47.7%

Blood Levels Associated With Active Disease

LOWERED

What This Means

Can be used to determine how hydrated a patient is. May also indicate an anaemia.

Platelet count

Other Names

Platelets

Function

Platelets help to stop bleeding by forming blood clots

Normal Levels

147-347 K/uL

Blood Levels Associated With Active Disease

ELEVATED

What This Means

Platelets are also elevated when there is inflammation in the body.

C-Reactive Protein

Other Names

CRP

Function

Elevations in CRP is not normally found in healthy individuals. It is a special type of protein produced in the liver that is present during episodes of acute inflammation or infection.

Normal Levels

Normal CRP values vary from lab to lab.

Blood Levels Associated With Active Disease

ELEVATED

What This Means

There is inflammation in the body.

Erythrocyte sedimentation rate

Other Names

ESR

Function

Measures the time taken for red blood cells to settle in a vertical tube.

Normal Levels

Normally, ESR levels are very low (undetectable).

Blood Levels Associated With Active Disease

ELEVATED

What This Means

There is inflammation in the body.

Liver Function Test

Other Names

LFT

Function

Gives some idea of liver function and the state of the biliary system (bile ducts).

Normal Levels

Multiple parameters are measured.

Blood Levels Associated With Active Disease

Depends on whether the liver is affected as an extraintestinal manifestations. Various medicines can also elevate the liver function tests.

What This Means

Usually requires a medical practitioner to interpret as multiple causes of elevated liver function tests exist.

Serum albumin

Other Names

SA

Function

Albumin is a protein made by the liver. A serum albumin test measures the amount of this protein in the clear liquid portion of the blood.

Normal Levels

3.4 - 5.4 g/dL

Blood Levels Associated With Active Disease

LOWERED

What This Means

Protein is being lost from the intestine or not being formed adequately.

peripheral antineutrophil cytoplasmic antibodies

Other Names

pANCA

Function

pANCA is an antibody to a type of white blood cell called a neutrophil.

Normal Levels

Less than 1.4 units/mL (less than 1.4 kilounits/L)

Blood Levels Associated With Active Disease

POSITIVE

What This Means

Proposed as a marker for ulcerative colitis, with 60–80% prevalence compared with 10% in Crohn's disease patients.

anti-saccharomyces cerevisiae antibody

Other Names

ASCA

Function

ASCA is another antibody, a type of white blood cell.

Normal Levels

ASCA-IgA ,10U/ml and ASCA-IgG <10U/m

Blood Levels Associated With Active Disease

ELEVATED

What This Means

These antibodies have 60–70% prevalence in Crohn's disease patients compared with 10–15% in ulcerative colitis and 0–5% in normal population.




MORE LINKS

If you are interested in other gastrointestinal-focused information and intervention websites developed and hosted at
Swinburne University of Technology,
please go to:

IBSclinic.org.au for individuals with Irritable Bowel Syndrome

Gastroparesisclinic.org for individuals with Gastroparesis

DISCLAIMER

This website and its content is not intended or recommended as a substitute for medical advice, diagnosis or treatment. Always seek advice of your own physician or other qualified health care professional regarding any medical questions or conditions.

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