Does alcohol affect blood test results?
The short answer
Yes. Alcohol can raise triglycerides and uric acid and can lower blood sugar, and regular heavier drinking is linked to raised liver enzymes such as GGT. JustLabs asks you to avoid alcohol for 24 hours before a lipid panel, and 48 hours before an NMR LipoProfile.
What to do
- Avoid alcohol for at least 24 hours before a lipid panel or Cardio IQ lipid panel, and 48 hours before an NMR LipoProfile.
- Don't drink during your fast; it is water only (black coffee is allowed for the Cardio IQ lipid panel).
- If you drank heavily the night before a lipid, glucose or uric acid test, consider rescheduling.
- Tell your clinician honestly how much you usually drink; it helps them read GGT, AST and triglycerides.
Which results it changes
| Marker | Effect | How long |
|---|---|---|
| Triglycerides[1] | Alcohol with a meal makes the after-meal rise bigger and longer | Hours after drinking; JustLabs asks for 24 hours without alcohol (48 hours for NMR LipoProfile) |
| Glucose[2] | Can fall (risk of low blood sugar), fasting or after a meal | Not well defined in our sources |
| Uric acid[3] | Rises; beer adds purines | Not well defined in our sources |
| GGT[4][5] | Raised by heavier, regular drinking; used as an alcohol marker | Depends on drinking pattern |
| AST and ALT[5] | Can rise with alcohol-related liver stress | Depends on drinking pattern |
Triglycerides: the main reason to skip a drink
Triglycerides naturally rise after a meal. Alcohol taken with a meal makes that rise bigger and makes it last longer, because ethanol briefly slows down lipoprotein lipase, the enzyme that clears triglycerides from the blood.
That matters for a lipid panel. A raised triglyceride level can also affect LDL cholesterol when LDL is calculated, as it is on the standard JustLabs lipid panel. This is why JustLabs asks you to avoid alcohol for 24 hours before a lipid panel or Cardio IQ lipid panel, and 48 hours before an NMR LipoProfile.
Blood sugar
Alcohol can raise the risk of low blood sugar (hypoglycemia), both when fasting and after a meal, in people with and without diabetes. One reason is that alcohol blocks gluconeogenesis, the liver's way of making new glucose.
Drinking the night before a fasting glucose test can therefore skew a result that is meant to show your usual fasting level.
Uric acid
Of the many factors that raise uric acid, a major review names alcohol as the most important. Ethanol speeds up the breakdown of compounds that turn into uric acid and raises lactic acid in the blood, which leads to higher uric acid. Beer also contains purines, which add to the rise.
Dehydration and exercise can add to the effect, so a big night out followed by a morning uric acid test is not a good combination.
Liver enzymes: GGT and AST
GGT is one of the classic lab markers clinicians use to look for heavier, regular drinking, along with other tests. Common liver enzymes such as AST and ALT can also point to liver stress caused by alcohol.
These markers are not only about alcohol. Their levels are also influenced by lifestyle factors such as weight gain, physical exercise and coffee. If your GGT or AST comes back high, your clinician will look at the whole picture, including how much you usually drink.
How long to avoid alcohol before a draw
We did not find a study that sets an exact number of alcohol-free hours before a blood test. For lipid tests, follow the JustLabs prep instructions: 24 hours for the lipid panel and the Cardio IQ lipid panel, 48 hours for the NMR LipoProfile.
JustLabs' lipase prep also notes that recent drinking may affect results. For other tests, there is no specific JustLabs alcohol rule, but skipping alcohol the day before is a simple way to get results that reflect your usual baseline.
Frequently Asked Questions
More on preparing
Sources
- Kovář J, Zemánková K. Moderate alcohol consumption and triglyceridemia. Physiol Res. 2015;64(Suppl 3):S371-5. doi: 10.33549/physiolres.933178. PMID: 26680670. PubMed
- Magis DC, Jandrain BJ, Scheen AJ. [Alcohol, insulin sensitivity and diabetes]. Rev Med Liege. 2003 Jul-Aug;58(7-8):501-7. PMID: 14579614. PubMed
- Yamamoto T, Moriwaki Y, Takahashi S. Effect of ethanol on metabolism of purine bases (hypoxanthine, xanthine, and uric acid). Clin Chim Acta. 2005 Jun;356(1-2):35-57. doi: 10.1016/j.cccn.2005.01.024. PMID: 15936302. PubMed
- Niemelä O. Biomarkers in alcoholism. Clin Chim Acta. 2007 Feb;377(1-2):39-49. doi: 10.1016/j.cca.2006.08.035. PMID: 17045579. PubMed
- Niemelä O. Biomarker-Based Approaches for Assessing Alcohol Use Disorders. Int J Environ Res Public Health. 2016 Jan 27;13(2):166. doi: 10.3390/ijerph13020166. PMID: 26828506. PubMed
Content reviewed for accuracy by the JustLabs editorial team.
Educational information, not medical advice. Don’t stop or change a prescribed medicine without talking to your prescriber. If your lab order gives different instructions, follow your lab order.