Hemoglobin A1c and Liver Transplantation
Understanding blood sugar before and after transplant
A1c is useful, but it may not tell the whole story. In cirrhosis, anemia, or after transfusion, compare it with glucose readings and your clinical history. [1] [2] [3]
What A1c Measures
A1c measures the percentage of hemoglobin with glucose attached. It summarizes blood sugar over about three months, with recent weeks contributing more than earlier weeks. It does not require fasting and cannot show every brief high or low. [1]
| A1c result | Usual interpretation |
|---|---|
| Below 5.7% | Below the prediabetes range |
| 5.7–6.4% | Prediabetes range |
| 6.5% or higher | Diabetes range; confirmation is generally needed without unequivocal hyperglycemia |
These diagnostic ranges are different from treatment goals. In cirrhosis or altered red-cell turnover, a result below the diabetes threshold does not reliably exclude diabetes. [1] [3]
Why Cirrhosis Can Make A1c Misleading
A1c depends on red-cell survival as well as glucose. A seemingly reassuring result may therefore underestimate blood sugar in advanced liver disease. [2] [3]
- Blood loss or hemolysis: younger circulating red cells can produce a falsely low A1c. [2]
- Iron deficiency: this can raise A1c; anemia does not always lower the result. [2]
- Transfusions, dialysis, or medicines that stimulate red-cell production: these can make A1c difficult to interpret. [1] [2]
- Hemoglobin variants: interference depends partly on the laboratory method. [2]
In a study of 100 people with cirrhosis, A1c missed some diabetes identified by an oral glucose tolerance test (OGTT). It performed less well in hospitalized patients and in those with moderate or severe anemia. A1c can still be useful, but should be checked against glucose measurements and the clinical situation. [3]
Before Transplant: Interpreting A1c Fairly
Transplant programs may use A1c in their assessment, but its ability to predict liver-transplant outcomes is limited. In a retrospective study of 173 recipients, preoperative A1c was not associated with most measured outcomes, including survival, rejection, or bacteremia. Higher A1c was associated with biliary anastomotic strictures and later insulin requirements. [4]
This observational finding does not establish a universal A1c cutoff for listing or prove that lowering A1c prevents those complications. Ask your center how it interprets your result alongside glucose records and other clinical information. A1c alone should not be treated as evidence of poor medication adherence. [4]
When results disagree, your team may arrange glucose-based testing, including an OGTT, rather than assuming a low A1c excludes diabetes. [3] [6]
After Transplant: Diabetes and Changing Results
Post-transplantation diabetes mellitus (PTDM) is an important complication after solid-organ transplantation. Immunosuppression contributes to risk, but protecting the graft remains essential. Do not change anti-rejection medication on your own; decisions require your transplant team. [6]
A1c may become more representative as blood abnormalities improve. In the liver-transplant study, its relationship with morning glucose was stronger after transplantation. An A1c change therefore needs interpretation alongside current glucose measurements. [4]
The 2024 international consensus emphasizes OGTT for screening and diagnosis because A1c can miss PTDM. Much of the evidence comes from kidney transplantation, so your liver team should tailor the approach. Early abnormalities may need reassessment once the clinical situation stabilizes. [6]
Individual Goals and Follow-Up
The ADA’s 2026 guidance considers an A1c below 7% appropriate for many nonpregnant adults when it can be achieved safely. Goals should account for hypoglycemia, frailty, other illnesses, treatment burden, and personal circumstances. This is not a universal transplant target. [5]
Stable diabetes may need A1c assessment twice yearly; changes in treatment or health, or glucose outside the agreed goals, often require assessment about every three months or more frequently. If A1c is unreliable, the team should use other measures. [5]
Complementary Tests and Monitoring
- Finger-stick glucose: measures blood sugar at a particular moment; timing and frequency should follow your care plan. [5]
- Continuous glucose monitoring (CGM): shows trends and time spent above, within, and below the chosen range. It complements A1c when results are misleading. [5]
- Fructosamine and glycated albumin: summarize approximately 2–4 weeks. Advanced liver disease can also reduce their reliability, so they are not automatically better substitutes. [4] [5]
- OGTT: measures the response to a glucose drink and can reveal diabetes missed by A1c. [3] [6]
Proposed combined measures such as CLD-A1c remain insufficiently validated for routine use. [4]
Practical Tips for Your Next Visit
Bring your glucose log or CGM report, recent A1c and blood-count results, and an updated medication list. Mention recent bleeding, transfusions, iron treatment, dialysis, or red-cell-stimulating medicines when discussing an unexpected A1c. [1] [2] [5]
- Ask whether A1c is trustworthy in your current circumstances.
- Agree on your glucose goals, monitoring schedule, and when to contact the team.
- Ask whether additional diagnostic testing is needed if A1c and glucose disagree.
- Discuss a plan for monitoring when transplant medicines change.
These conversation prompts reflect the need for individualized assessment and coordinated diabetes and transplant care. [5] [6]
Verified Sources and References
Highlighted citation numbers throughout the page open the corresponding source in a new tab. The full source links below are also highlighted, bold, and underlined.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The A1C Test & Diabetes. Patient education resource.
- NGSP. Factors that Interfere with HbA1c Test Results. Updated June 23, 2026.
- Sehrawat T, et al. Utility and Limitations of Glycated Hemoglobin (HbA1c) in Patients with Liver Cirrhosis as Compared with Oral Glucose Tolerance Test for Diagnosis of Diabetes. Diabetes Therapy. 2018;9:243–251. doi:10.1007/s13300-017-0362-4.
- Gray M, Singh S, Zucker SD. Influence of Type 2 Diabetes Mellitus and Preoperative Hemoglobin A1c Levels on Outcomes of Liver Transplantation. Hepatology Communications. 2019;3(4):574–586. doi:10.1002/hep4.1323.
- American Diabetes Association Professional Practice Committee for Diabetes. 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1). doi:10.2337/dc26-s006.
- Sharif A, et al. International consensus on post-transplantation diabetes mellitus. Nephrology Dialysis Transplantation. 2024;39(3):531–549. doi:10.1093/ndt/gfad258.