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22813 Lactose Tolerance

Lactose Tolerance
Test Code: LTT
Synonyms/Keywords
​LTT​
Useful For
In testing for lactose activity, an oral lactose dose is given.  Blood specimens are drawn at designated intervals following the ingestion of lactose and analyzed for glucose.​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)

​Yes

9-12 Hours

 Plasma​/Serum Lithium-heparin Plasma Separator (PST), Serum Separator Tube (SST) Lithium or Sodium-heparin Green Top (GTT)​, Red Top Tube (RTT), Gray Top Tube (GYTT) 1 mL​ 0.3 mL​ ​
Collection Processing Instructions
Call Clinic Pharmacy for Lactose dose.  Baseline should be drawn just prior to patient taking lactose dose, and susequent draws after dosing. 

Specimens routinely drawn for baseline, and then 30, 60, 90 and 120 minutes post lactose dosing. Specimens analyzed for glucose.
 
Usual adult test dose is 50 g. Lactose. Usual pediatric test dose is 1.75 g/Kg body weight (not to exceed 50 g.). Adult patients should be fasting for a minimum of 8 hours prior to the start of the test and should not eat until after the last blood specimen has been drawn.​
Specimen Stability Information
Specimen Type Temperature

Time

Plasma​/Serum ​ Refrigerate​ 1 week​
Frozen​ 1 year​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Park Falls
 ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 2 hours​ Hexokinase-UV/NAD Endpoint Assay/Beckman AU
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Neillsville​Monday through Sunday​​Less than 2 hours​​​​Modified Hexokinase Method/Siemens Dimension
Reference Range Information
Performing Location Reference Range
All Performing Sites ​ Baseline (Fasting) Glucose: 70-99 mg/dL​
Rise in blood glucose of at least 20 mg/dL above baseline concentration within 90 minutes post 50 g. lactose dose (adult)​
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82951 ​ ​ ​ First three specimens ​ ​
82952​ ​

2​

 Each additional specimen ​ ​
Synonyms/Keywords
​LTT​
Ordering Applications
Ordering Application Description
​Cerner ​Lactose Tolerance Test

If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)

​Yes

9-12 Hours

 Plasma​/Serum Lithium-heparin Plasma Separator (PST), Serum Separator Tube (SST) Lithium or Sodium-heparin Green Top (GTT)​, Red Top Tube (RTT), Gray Top Tube (GYTT) 1 mL​ 0.3 mL​ ​
Collection Processing
Call Clinic Pharmacy for Lactose dose.  Baseline should be drawn just prior to patient taking lactose dose, and susequent draws after dosing. 

Specimens routinely drawn for baseline, and then 30, 60, 90 and 120 minutes post lactose dosing. Specimens analyzed for glucose.
 
Usual adult test dose is 50 g. Lactose. Usual pediatric test dose is 1.75 g/Kg body weight (not to exceed 50 g.). Adult patients should be fasting for a minimum of 8 hours prior to the start of the test and should not eat until after the last blood specimen has been drawn.​
Specimen Stability Information
Specimen Type Temperature

Time

Plasma​/Serum ​ Refrigerate​ 1 week​
Frozen​ 1 year​
Useful For
In testing for lactose activity, an oral lactose dose is given.  Blood specimens are drawn at designated intervals following the ingestion of lactose and analyzed for glucose.​
Reference Range Information
Performing Location Reference Range
All Performing Sites ​ Baseline (Fasting) Glucose: 70-99 mg/dL​
Rise in blood glucose of at least 20 mg/dL above baseline concentration within 90 minutes post 50 g. lactose dose (adult)​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Park Falls
 ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 2 hours​ Hexokinase-UV/NAD Endpoint Assay/Beckman AU
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Neillsville​Monday through Sunday​​Less than 2 hours​​​​Modified Hexokinase Method/Siemens Dimension
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82951 ​ ​ ​ First three specimens ​ ​
82952​ ​

2​

 Each additional specimen ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.