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HelpTest Code DLAU D-Lactate, Urine
Reporting Name
D-Lactate, UUseful For
Preferred test for diagnosing D-lactate acidosis, especially in patients with jejunoileal bypass and short-bowel syndrome
Method Name
Gas Chromatography Mass Spectrometry (GCMS) Stable Isotope Dilution Analysis
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineSpecimen Required
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic urine tube
Specimen Volume: 0.50 mL
Collection Instructions:
1. Collect a timed or random urine specimen.
2. No preservative.
3. Immediately freeze specimen.
Specimen Minimum Volume
0.15 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen (preferred) | 90 days | |
| Ambient | 90 days | ||
| Refrigerated | 90 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Special Instructions
Reference Values
0.0-0.25 mmol/L
Day(s) Performed
Monday, Thursday
CPT Code Information
83605
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| DLAU | D-Lactate, U | 14046-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8873 | D-Lactate, U | 14046-7 |
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.Clinical Information
D-lactate is produced by bacteria residing in the colon when carbohydrates are not completely absorbed in the small intestine. When large amounts of D-lactate are present, individuals can experience metabolic acidosis, altered mental status (from drowsiness to coma) and a variety of other neurologic symptoms, in particular dysarthria and ataxia. Although a temporal relationship has been described between elevations of plasma and urine D-lactate and the accompanying encephalopathy, the mechanism of neurologic manifestations has not been elucidated.
D-lactic acidosis is typically observed in patients with a malabsorptive disorder, such as short-bowel syndrome, or following jejunoileal bypass. In addition, healthy children presenting with gastroenteritis may also develop the clinical presentation of D-lactic acidosis.
Routine lactic acid determinations in blood will not reveal abnormalities because most lactic acid assays measure only L-lactate. Accordingly, D-lactate analysis must be specifically requested (eg, DLAC / D-Lactate, Plasma). However, as D-lactate is readily excreted in urine, this is the preferred specimen for D-lactate determinations.
Interpretation
Increased levels are diagnostic.
Cautions
The test performed is for D-lactate. This is a product of bacterial overgrowth in the gastrointestinal tract. It should not be confused with L-lactate, which accumulates in some metabolic acidosis.
Method Description
Urine is spiked with a mixture of internal standards and evaporated. The dry residue is derivatized with DATAN to form the diastereomeric molecules, then acidified and extracted with ethyl acetate. After evaporation, the dry residue is again derivatized to form trimethylsilyl (TMS) esters at the carboxylic acid moiety. Specimens are then analyzed by capillary gas chromatography mass spectrometry selected ion monitoring using positive chemical ionization with chromatographic separation of the L,L- and D,L-diastereoisomers of derivatized lactate, corresponding to L-Lactate and D-Lactate, respectively.(Ding X, Lin S, Weng H, Liang J. Separation and determination of the enantiomers of lactic acid and 2-hydroxyglutaric acid by chiral derivatization combined with gas chromatography and mass spectrometry. J Sep Sci. 2018;41(12):2576-2584)