Type of test Blood

 Normal findings

 Cord: 45-96 mg/dL or 2.5-5.3 mmol/L (SI units)

 Premature infant: 20-60 mg/dL or 1.1-3.3 mmol/L

 Neonate: 30-60 mg/dL or 1.7-3.3 mmol/L

Infant: 40-90 mg/dL or 2.2-5 mmol/L

Child < 2 years: 60-100 mg/dL or 3.3-5.5 mmol/L

Child > 2 years to adult: Fasting: 70-110 mg/dL or < 6.1 mmol/L (Fasting is defined as no caloric intake for at least 8 hours.)

Casual: ≤ 200 mg/dL (< 11.1 mmol/L) (Casual is defined as any time of day regardless of food intake.)

 Adult: 74-106 mg/dL or 4.1-5.9 mmol/L

 Elderly: 60-90 years: 82-115 mg/dL or 4.6-6.4 mmol/L

 > 90 years: 75-121 mg/dL or 4.2-6.7 mmol/L

Possible critical values

 Adult: < 50 and > 400 mg/dL

Infant: < 40 mg/dL

Newborn: < 30 and > 300 mg/Dl

Test explanation and related physiology

Through an elaborate feedback mechanism, glucose levels are controlled by insulin and glucagon. Serum glucose levels must be evaluated in relation to meal time. For example, a glucose level of 135 mg/dL may be abnormal if the patient is in the fasting state, but this level would be within normal limits if the patient had eaten a meal within the previous hour.

In general, true glucose elevations indicate diabetes mellitus; however, one must be aware of many other possible causes of hyperglycemia. Similarly, hypoglycemia has many causes. The most common cause is inadvertent insulin overdose in patients with brittle diabetes. If diabetes is suspected by elevated fasting blood levels, glycosylated hemoglobin (p. 473) or glucose tolerance tests (p. 469) can be performed.

Glycosylated hemoglobin is now being performed more frequently to identify diabetes because this blood test represents blood sugar levels over the previous 120 days. Glucose determinations may be performed frequently in new patients with insulin-dependent diabetes to monitor closely and adjust the insulin dosage. Finger stick blood glucose determinations are often performed before meals and at bedtime.

For minimally invasive monitoring, a small, sterile, disposable glucose-sensing device is inserted into the subcutaneous tissue (usually the arm). This sensor measures the change in glucose in the interstitial fluid. This information is recorded in a small beeper-sized monitor for 3 to 4 days. The monitor is taken to the doctor’s office, where it is connected to a standard personal computer. Specialized software then downloads the stored information, and a more effective insulin regimen can be developed.

Interfering factors

 • Many forms of stress (e.g., general anesthesia, cerebrovascular accident, myocardial infarction, shock, strenuous exercise, burns) can cause increased serum glucose levels.

• Many pregnant women experience some degree of glucose intolerance. If significant, it is called gestational diabetes.

* Most IV fluids contain dextrose, which is quickly converted to glucose. Therefore patients receiving IV fluids may have increased glucose levels.

*  Drugs that may cause increased levels include antidepressants (tricyclics), antipsychotics, beta-adrenergic blocking agents, corticosteroids, cyclosporine, dextrose IV infusion, dextro thyroxine, diazoxide, diuretics, epinephrine, estrogens, glucagon, isoniazid, lithium, niacin, phenothiazines, phenytoin, salicylates (acute toxicity), statins, and triamterene.

*  Drugs that may cause decreased levels include acetaminophen, alcohol, alpha-glucosidase inhibitors, anabolic steroids, biguanides, clofibrate, disopyramide, gemfibrozil, incretin mimetics, insulin, meglitinides, monoamine oxidase inhibitors, pentamidine, propranolol, sulfonylureas, and thiazolidinediones.

Procedure and patient care

 • See inside front cover for Routine Blood Testing.

 • Fasting: yes

 • Blood tube commonly used: red or gray

* For FBS, instruct the patient to fast for 8 hours. Water is permitted.

* To prevent starvation, which may artificially raise the glucose levels, tell the patient not to fast much longer than 8 hours.

 • Withhold insulin or oral hypoglycemics until after blood is obtained.

• Glucose levels also can be evaluated by performing a fin ger stick and using either a visually read test or a reflectance meter. Using reflectance meters (e.g., glucometer, Accu-Chek bG, Stat-Tek) improves the accuracy of the blood glucose determination.

 Abnormal findings

 Increased levels

 -(hyperglycemia)

 -Diabetes mellitus

 -Acute stress response

 -Cushing syndrome

 -Pheochromocytoma

-Chronic renal failure

 -Glucagonoma

 -Acute pancreatitis

 -Diuretic therapy

-Corticosteroid therapy

-Acromegaly

Decreased levels

- (hypoglycemia)

- Insulinoma

- Hypothyroidism

- Hypopituitarism

- Addison disease

- Extensive liver disease

- Insulin overdose

- Starvation

مواضيع ذات صلة

α1-antitrypsin

Albumin

Diagnostic Laboratory Tests for Mycobacterium Tuberculosis

Gliadin, endomysial, and tissue transglutaminase antibodies

Antimicrobial Susceptibility Testing and Therapy of Staphylococcus, Micrococcus, and Similar Organisms

Glucagon

genetic testing (Breast cancer [BRCA] and ovarian cancer, Colon cancer, Cardiovascular disease, Tay–Sachs disease, Cystic fibrosis, Melanoma, Hemochromatosis, Thyroid cancer, Paternity [parentage analysis], Forensic genetic testing)

Tuberculin Test

Clinical Relevance of Plasma Cell Dyscrasias

Liver Cancers

Biomarkers of Alcoholism

Gastrin