Davis's Lab & Diagnostic Tests
Glucose, 1-5 Anhydroglucitol, and Fructosamine
General
Core Lab Study
Synonym/Acronym:
Blood sugar, fasting blood sugar (FBS), postprandial glucose, 2-hr PC (post cibum).
Rationale
To assist in the diagnosis, treatment, and management of diabetes.
A small group of studies in this manual have been identified as Core Lab Studies. The designation is meant to assist the reader in sorting the basic “always need to know” laboratory studies from the hundreds of other valuable studies found in the manual—a way to begin putting it all together.
Normal, abnormal, or various combinations of core lab study results can indicate that all is well, reveal a problem that requires further investigation with additional testing, signal a positive response to treatment, or suggest that the health status is as expected for the associated situation and time frame.
Glucose is mainly used to screen and assess for diabetes. Glucose is included in the basic metabolic panel (BMP), comprehensive metabolic panel (CMP), diabetes profile, obstetric panel, pancreatic profile, and renal function panel. Panels are used as general health and targeted screens to identify or monitor conditions such as bone disease, diabetes, hypertension, kidney disease, liver disease, or malnutrition.
Patient Preparation
There are no activity or medication restrictions unless by medical direction. There are no restrictions for the random glucose test. Instruct the patient to fast for at least 8 hr before specimen collection for the fasting glucose test and not to consume any caffeinated products or chew any type of gum before specimen collection; these factors are known to elevate glucose levels. Instruct the patient to follow the instructions given for 2-hr postprandial glucose test. Some health-care providers (HCPs) may order administration of a standard glucose solution, whereas others may instruct the patient to eat a meal with a known carbohydrate composition.
Normal Findings
Method: Spectrophotometry for Glucose, 1-5 Anhydroglucitol, and Fructosamine.
| Age | Conventional Units | SI Units (Conventional Units × 0.0555) | |||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nondiabetic, fasting | |||||||||||||||||||||||||||||||||||||||||
| Cord blood | 45–96 mg/dL | 2.5–5.3 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Premature infant | 20–80 mg/dL | 1.1–4.4 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Newborn 2 days–2 yr | 30–100 mg/dL | 1.7–5.6 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Child | 60–100 mg/dL | 3.3–5.6 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Adult–older adult | Less than 100 mg/dL | Less than 5.6 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Nondiabetic, 2-hr postprandial | 65–139 mg/dL | 3.6–7.7 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Nondiabetic, random | Less than 200 mg/dL | Less than 11.1 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Prediabetic, fasting | 100–125 mg/dL | 5.6–6.9 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Prediabetic, 2-hr postprandial | 140–199 mg/dL | 7.8–11 mmol/L | |||||||||||||||||||||||||||||||||||||||
| Fasting means no caloric intake for 8 hr or longer. Values tend to increase in older adults. | |||||||||||||||||||||||||||||||||||||||||
| 1-5, Anhydroglucitol (Short-term indicator of good glycemic management) | |
| Male | 10.7–32 mcg/mL |
| Female | 6.8–29.3 mcg/mL |
| Fructosamine (Glycated albumin) | ||
| Conventional Units | SI Units (Conventional Units × 0.01) | Status |
| 205–286 micromol/L | 3.05–2.86 mmol/L | Nondiabetic |
| 210–563 micromol/L | 2.10–5.63 mmol/L | Diabetic (values vary with degree of management) |
Critical Findings and Potential Interventions
Glucose
Adults & children
- Less than 40 mg/dL (SI: Less than 2.22 mmol/L)
- Greater than 400 mg/dL (SI: Greater than 22.2 mmol/L)
Newborns
- Less than 32 mg/dL (SI: Less than 1.8 mmol/L)
- Greater than 328 mg/dL (SI: Greater than 18.2 mmol/L)
Timely notification to the requesting HCP of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.
Consideration may be given to verification of critical findings before action is taken. Policies vary among facilities and may include requesting immediate recollection and retesting by the laboratory or retesting using a rapid point-of-care testing instrument at the bedside, if available.
Glucose monitoring is an important measure in achieving tight glycemic management. Glucose meters that use the enzymatic GDH-PQQ test strips may produce falsely elevated results in patients who are receiving products that contain other sugars (e.g., oral xylose, parenterals containing maltose or galactose, and peritoneal dialysis solutions that contain icodextrin, a metabolite of maltose). Glucometers that use GDH-NAD, GDH-FAD, and glucose oxidase test strips are specific for glucose and do not detect other sugars. Clinical laboratories do not use the GDH-PQQ method or reagents to determine glucose levels.
Symptoms of decreased glucose levels include headache, confusion, polyphagia, irritability, nervousness, restlessness, diaphoresis, and weakness. Possible interventions include oral or IV administration of glucose, IV or intramuscular injection of glucagon, and continuous glucose monitoring.
Symptoms of elevated glucose levels include abdominal pain, fatigue, muscle cramps, nausea, vomiting, polyuria, polyphagia, and polydipsia. Possible interventions include fluid replacement in addition to subcutaneous or IV injection of insulin with continuous glucose monitoring.
There's more to see -- the rest of this topic is available only to subscribers.
