Sign in →

Test Code 8129 Lactose Tolerance Test, Blood

Performing Laboratory

Barnes-Jewish Hospital Laboratory


Enzymatic (Hexokinase)

Note: Laboratory will analyze as glucose.

Literature Reference:

Package insert: Glucose/HK reagent. Roche Corporation, 03/2006.

Specimen Requirements

Patient Preparation:Patient must fast overnight.


Specimen Type: Plasma
Container/Tube: Grey top (potassium oxalate/sodium fluoride)
Specimen Volume: Full tube

Collection Instructions:

1. Draw fasting specimen.
2. Give patient 50 g of lactose in 200 mL of water, to be consumed within 5 minutes.
3. Draw specimens at 15-, 30-, 45-, 60-, and 120-minutes post consumption.

Additional Information: Draw times are required on each specimen.

Day(s) Test Set Up

Monday through Sunday
Turnaround Time:
STAT: 1 hour after receipt in laboratory
Routine: 2 to 4 hours after receipt in laboratory

Reference Values

Fasting specimen: 65-99 mg/dL

Lactate deficient: less than a 20 mg/dL increase in glucose between fasting specimen and any 1 specimen
Indeterminate: 20-30 mg/dL increase in glucose
Normal: greater than a 30 mg/dL increase in glucose

Test Classification and CPT Coding

82951-Glucose tolerance test, 3 specimens
82952-Glucose tolerance test, each additional specimen

Additional Information

For BJH Laboratory Use Only
Alternate Tube:

1 dark green-top (lithium heparin) tube

1 lavender-top (EDTA) tube
1 red-top tube
Analyte Stability:

See Analyte Stability Chart in Special Instructions.

Laboratory Processing Instructions:

Test performed in BJH Chemistry. Centrifuge upon receipt. Deliver to the (Modular in Chemistry, RXL in the North Campus Laboratory). Completed specimen is stored refrigerated for 1 week.

Specimen Transport Temperature


Special Instructions

LOINC Code Information

Name LOINC Code
Glucose- pre dose lactose PO 59157-8
Glucose- 30 minutes post 50G lactose PO 14762-9
Glucose- 45 minutes post 50G lactose PO 45299-5
Glucose- 1 hour post 50G lactose PO 14755-3
Glucose- 2 hours post 50G lactose PO 14758-7