Gastroenterology Clinical Lab

Disaccharidases are enzymes found in the luminal (brush border membrane) of intestinal cells and are responsible for digestion of disaccharides. Disaccharides activity, including lactase, maltase, sucrase, palatinase and glucoamylase, can be determined from an intestinal biopsy. 

Higher activity levels usually are not clinically significant. If the activities are too low, it can lead to digestive problems like diarrhea, abdominal pain or bloating. Lower activity can be due to intestinal damage or a specific enzyme deficiency, which could be inherited or acquired over time.

Biopsy Collection Instructions

• Collect a 2 to 5 mg wet weight intestinal biopsy.
• Place the sample in a small, tightly sealed plastic tube.
• Immediately place the tube on dry ice or store at -20°C to -70°C.
• The biopsy should not be placed on gauze or a toothpick, nor should any solutions be added. 
• Biopsies should be collected prior to surgical samples for pathology to avoid contamination from formalin.
• Ship with enough dry ice to keep the sample frozen.

Assay Limitation Summary

Note: Assay normal ranges are based on normal sample or medical conditions. Samples with the following abnormal conditions might affect the results. Clinical correlation is advised if abnormal test results are found. There are always unknown factors that might limit the assay.

• Homogenates from biopsies should have protein ≥ 0.2 mg/ml. Recommend biopsy size is 2 to 5 mg wet weight. Extremely low protein content from very small samples might lead to abnormal findings, thus the results are unreliable. 
• Biopsies should contain most of mucosal tissue not muscle or connective tissue. Muscle tissue lacks the enzymatic activities, thus leading to false abnormal results. It is difficult to distinguish a muscle biopsy from mucosal biopsy when samples are processed.

The pancreas releases the enzymes amylase, lipase, trypsin, chymotrypsin and elastase into the digestive tract. Enzyme activity can be measured in the pancreatic juice collected by duodenal intubation. 

Elevated enzyme levels typically are not medically concerning. Reduced levels can indicate pancreatic issues like chronic pancreatitis or cystic fibrosis. Reduced levels could also be due to isolated enzyme deficiency, which might be temporary in early infancy, or a permanent congenital enzyme deficiency.

Sample Collection Instructions

• Collect a minimum of 1 cc of a single fluid or multiple fluid samples.
• Place the sample in a small, tightly capped plastic tube.
• Freeze the sample on dry ice or at -20°C. 
• Ship with enough dry ice to keep the sample frozen.

Assay Limitation Summary

Note: Assay normal ranges are based on normal sample or medical conditions. Samples with the following abnormal conditions might affect the results. Clinical correlation is advised if abnormal test results are found. There are always unknown factors that might limit the assay.

Samples with the following conditions might produce false abnormal results:

• Acidic pH at <7, particularly at pH 5 or less, might indicate gastric contamination which might happen during sample collection. At such low pH, pancreatic enzymes are unstable and degraded rapidly.
• Extremely high protein content (>20 mg/m) might indicate bile contamination. Bile lacks pancreatic enzyme activities. 
• On the other hand, extremely low protein content (<0.2 mg/ml) might indicate low secretion, either from a failed stimulation during sample collection or low secretion deficiency physiologically. 

Pepsin A is expressed exclusively in the gastric mucosa, thus detection of pepsin A in the airway is a specific marker of airway aspiration. Airway aspiration from stomach contents can lead to respiratory problems like coughing, choking, or pneumonia. We offer a sensitive, reliable enzymatic assay to detect gastrin pepsin A in tracheal and bronchial secretions.

Sample Collection Instructions

• Collect a minimum of 1 cc of fluid.
• Avoid over-diluting the secretion with saline.
• Place the sample in a small, tightly capped plastic tube.
• Freeze the sample immediately on dry ice or at -20°C.
• Ship with enough dry ice to keep the sample frozen.

For tracheal secretion, attach a Luki trap to a suction catheter, pass it down the endotracheal tube and suction while pulling it out. If it's too thick, add 2 cc of saline to the tube before aspirating.

For bronchial secretion, follow standard collection procedures. Collect 1 to 2 cc of fluid in a plain specimen tube. 

Assay Limitation Summary

Note: Assay normal ranges are based on normal sample or medical conditions. Samples with the following abnormal conditions might affect the results.

• Pepsin A is rapidly degraded in alkaline pH (>6.0) as pepsin is not stable at alkaline condition. Samples with pH >6 might have reduced activity, resulting in negative pepsin.   
• Absence of protein content or extremely low (<0.01 mg/ml) in a sample might indicate sample over dilution during collection, which can also lead to negative pepsin.
• High protein contents (>2 mg/ml or higher) in a sample might interfere enzymatic activity, thus decrease pepsin concentration. If borderline positivity was discovered in a high protein sample, assay might be repeated by diluting sample protein to 2 mg/ml.  

A negative result does not rule out a micro-aspiration event. The detection of pepsin A in the airway is determined by the time of the aspiration, the degree of the aspiration, and the pH of the aspirates in the final collected media. Results from this assay should be used in conjunction with clinical findings and other lab results. 

Celiac disease is a long-term immune reaction to gluten in kids with a genetic predisposition (runs in the family). It triggers specific antibodies in the blood, which we can detect through serological tests. We offer four specific serology celiac markers:

• Tissue transglutaminase antibody IgA (tTG IgA)
• Tissue transglutaminase antibody IgG (tTG IgG)
• Deamidated gliadin peptide antibody IgA (DGP IgA)
• Deamidated gliadin peptide antibody IgG (DGP IgG)

A positive result shows the presence of celiac disease-related antibodies, which indicates possible gluten-related intestinal issues. Combined with clinical examination and other tests, the results help diagnose celiac disease and monitor dietary adherence.  

Sample Collection Instructions

• Collect a minimum sample of 0.5 cc.
• Avoid using grossly hemolyzed or lipemic serum specimens (appear very red or milky).
• Separate the serum from any clots.
• Place the sample in a small tightly capped plastic tube without additives.
• For up to 8 hours, the sample can be kept at room temperature.
• For longer than 8 hours, refrigerate the sample at 2°C to 8°C.
• For longer than 48 hours, freeze the sample at -20°C.
• Ship the sample with dry ice.

Assay Limitation Summary

Note: Assay normal ranges are based on normal sample or medical conditions. Samples with the following abnormal conditions might affect the results. Clinical correlation is advised if abnormal test results are found. There are always unknown factors that might limit the assay.

Heavily hemolyzed serum might give unreliable results. Other medical conditions might limit the assay. Below is provided by the test kit manufacturer.

• This kit is used to aid diagnosis only. A positive result suggests certain diseases that must be confirmed by clinical findings and other serological tests.
• The results obtained from this assay are not diagnostic proof of the presence or absence of disease.
• The use of this assay and normal range (result interpretation) has not been established for pediatric samples.
• A negative result may be due to IgA deficiency and does not rule out coeliac disease.

Calprotectin is a protein made by polymorphonuclear leukocytes, monocytes, and squamous epithelial cells. Calprotectin in the stool increases significantly when there is inflammation (redness and swelling) in the intestine, which could be a sign of inflammatory bowel disease. 

We can detect calprotectin in a small amount of stool (less than 1 g) using an Elisa assay.

Sample Collection Instructions

• Collect 1 to 5 g of loose or liquid stool.
• Avoid using stool that has contact with diaper material. 
• Place the sample in a clean screw-top vial without preservatives.
• For up to 4 days, refrigerate the sample at 2°C to 8°C.
• For longer than 4 days, freeze the sample at -20°C.
• Ship the sample with dry ice.

Assay Limitation Summary

Note: Assay normal ranges are based on normal sample or medical conditions. Samples with the following abnormal conditions might affect the results. Clinical correlation is advised if abnormal test results are found. There are always unknown factors that might limit the assay.

Loose or blood stool might give unreliable results. Other medical conditions might limit the assay. Below is provided by the test kit manufacturer:

• Fecal calprotectin is an indicator of neutrophilic presence in the stool, not specific for IBD. Therefore, drug usage and conditions can influence the levels.
• False-negative results could occur in patients who have granulocytopenia due to bone marrow depression.
• False positive or elevated calprotectin levels might occur:
  • Steroid anti-inflammatory drugs and proton pump inhibitors
  • Microscopic colitis, diverticular disease, untreated celiac disease, gastrointestinal infections, colorectal cancer
• When use the extended kit, the fluctuation between active and inactive stage of IBD patients must be considered.