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HelpTest Code LTT Lactose Tolerance
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.
Synonyms/Keywords
LTT
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 |
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) |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Sunday | Less than 2 hours | Hexokinase-UV/NAD Endpoint Assay/Beckman AU |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82951 | 1 | First three specimens | ||
| 82952 |
2 |
Each additional specimen |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82951 | 1 | First three specimens | ||
| 82952 |
2 |
Each additional specimen |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Lactose Tolerance Test |