Lab Tests
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
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.
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.
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.