Lactose Tolerance

Last Modified: 1/15/2020 10:14:25 AM

Client Notes:

Please remind patients of the time frame this testing will take, and that they need to be at the drawsite in plenty of time before closing.

Tolerance collections are only performed at Parkview Outpatient Center, 11141 Parkview Plaza Drive, Suite 100 Fort Wayne, IN 46845 Entrance 3 

Patient Preparation:
This test is not to be performed on infants or very young children (<6 yrs. of age), because they are more prone to dehydration that can result from diarrhea caused by the lactose. 
Patient to fast for at least 10 hours and up to 14 hours

This test will take approximately 3 hours, and patient will need to remain in the outpatient area during that time.

No smoking, drinking, or eating, including gum, mints, cough drops, etc., is allowed during the test. Small amounts of water are allowed after the 1 hour specimen is drawn. Medication may still be taken as ordered by the physician; if possible, these should be noted.
Specimen Requirements:

1.0 mL Plasma from a Grey Top Tube - Na Flouride K+ in a Plastic Vial for each of the 5 draws

Collection Instructions: Collect fasting, 30, 60, 120, and 180 minutes after ingestion of 50 g of lactose. 

Immediately after a fasting specimen is obtained, have patient ingest a 50 g dose of lactose (supplied by the laboratory) draw subsequent specimens 1/2, 1, 2 and 3 hours later. Label each with the specific draw time.

Please note: Children should receive 1.75 g lactose per kg ideal body weight, up to 50 g.

Record the date and time of collection on EACH specimen and on the request form.

Minimum Volume: 0.5 mL Plasma x 5
Transport & Storage: Temperature/Stability: 7 days Ambient
7 days Refrigerated
28 days Frozen
Rejection Criteria: Unspun Serum Separator Tube (SST); anticoagulants other than lithium or sodium heparin or fluoride/oxalate; red-top or non-plasma separator green top tubes
Reference Range: Increase of Glucose less than 20 mg/dL over the fasting level is suggestive of an enzyme defect.
Methodology: Spectrophotometry
Clinical Significance:
Results may be used to evaluate deficiency of small bowel mucosal lactase, which may be associated with intolerance to lactose, manifested by diarrhea and other symptoms following ingestion of milk.
Custom Panel: No


Turn Around Time: 4 days
Days Performed: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday
Sites Performed: Parkview Regional Medical Center, Quest - Chantilly
PHL Test Code: 5MSOT
EPIC Test Code:
Send Out Test Code: 7675
Included Tests:

Glucose Fasting, Plasma; Glucose, 30 min.,Plasma; Glucose, 1 hr., Plasma; Glucose, 2 hr Plasma; Glucose, 3 hr. Plasma

CPT Coding: 82951 & 82295 x2 (82951 for first 3 specimens, 82952 each additional specimen)

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