Diagnostic Tests for Diabetes-like symptoms
Diagnostic Test list for Diabetes-like symptoms:
The list of diagnostic tests
mentioned in various sources as
used in the diagnosis of Diabetes-like symptoms
includes:
- Physical examination
- Examine for signs of complications of Diabetes mellitus including cataracts, diabetes retinopathy, hypertension, ischemic heart disease, stroke, peripheral vascular disease, candida skin and genital infections, peripheral neuropathy
- Examine for signs of secondary causes of hyperglycaemia (elevated blood sugar) - e.g. Cushing's syndrome, hemochromatosis, Conn's syndrome, cystic fibrosis, acromegaly.
- Blood tests
- Fasting blood sugar level - Diagnosis of Diabetes mellitus requires fasting blood sugar level to be greater or equal to 7.0 mmol/L.
- Random blood sugar level - Diagnosis of Diabetes mellitus requires random blood sugar level to be greater or equal to 11.1 mmol/L and the person must also have symptoms of elevated blood sugar including frequent urination, excessive thirst and unexplained weight loss.
- 2 hour post 75g Oral glucose tolerance test - for diagnosis of Diabetes mellitus in borderline cases or for diagnosis of gestational diabetes with a blood glucose level of greater or equal to 11.1 mmol/L.
- All pregnant women should be advised to have a screening oral glucose tolerance test at around 26-30 weeks gestation
- Diagnosis of Impaired glucose tolerance requires fasting blood glucose of less than 7.0 mmol/L AND 2 hour post 75g Oral glucose tolerance test with a blood glucose level of greater than or equal to 7.8 mmol/L and less than 11.1 mmol/l
- HbA1C - measures the average blood glucose level over the past 3 months.
- Electrolytes - looking for signs of dehydration due to any of the causes of diabetes-like symptoms; look for reduced potassium seen in Conn's syndrome.
- Renal function test - to detect any damage to kidneys.
- Fasting blood lipids, including total cholesterol, LDL, HDL, triglycerides
- Plasma ADH assay and plasma osmolality - if suspect Diabetes insipidus.
- Iron studies and liver function tests - if suspect hemochromatosis as a secondary cause of elevated blood sugar ( look for elevated ferritin and a transferring saturation of greater than 60%).
- If suspect Acromegaly as a secondary cause of elevated blood sugar, test for increased fasting growth hormone and insulin-like growth factor 1
- If suspect Conn's syndrome as a secondary cause of elevated blood sugar, test for an inappropriately elevated aldosterone and a reduced plasma renin activity. A plasma aldosterone (PA) : plasma renin activity (PRA) ratio over greater than 20 suggests Conn's syndrome
- If suspect Cushing's syndrome as secondary cause of elevated blood sugar, test for a suppressed Dexamethasone suppression test
- Urine tests
- 24 hour Urine microalbumin - to check for any damage to the kidneys due to diabetes.
- Water deprivation test - if suspect diabetes insipidus.
- If suspect Conn's syndrome, test for increased 24 hour urinary aldosterone
- If suspect Cushing's syndrome, test for increased 24 hour free cortisol
- If suspect phaeochromocytoma, test fro increased 24 hour urinary free catecholamines and increased urine metadrenalines and normetadrenaline
- Radiological investigations
- Upper abdominal ultrasound and CT scan - if suspect chronic pancreatitis.
- CT brain - if suspect Acromegaly or Cushing's disease, looking for pituitary tumor.
- Liver biopsy - if suspect hemochromatosis.
Home Diagnostic Testing
These home medical tests may be relevant to Diabetes-like symptoms causes:
- High Cholesterol: Home Testing:
- High Blood Pressure: Home Testing
- Heart Health: Home Testing:
- Thyroid: Home Testing:
- Menopause: Related Home Testing:
- Vaginal Health: Home Testing:
- Diet & Weight Loss: Home Testing:
- Adrenal Gland Health: Home Testing:
- Breast Cancer: Related Home Tests:
- Kidney Health: Home Testing:
- Diabetes: Related Home Testing:
Tests and diagnosis discussion for Diabetes-like symptoms:
The fasting plasma glucose test is the preferred test for diagnosing
type 1 or type 2 diabetes. However, a diagnosis of diabetes is made for
any one of three positive tests, with a second positive test on a
different day:
- A random plasma glucose value (taken any time of day) of 200 mg/dL
or more, along with the presence of diabetes symptoms.
- A plasma glucose value of 126 mg/dL or more, after a person has
fasted for 8 hours.
- An oral glucose tolerance test (OGTT) plasma glucose value of 200
mg/dL or more in the blood sample, taken 2 hours after a person has
consumed a drink containing 75 grams of glucose dissolved in water. This
test, taken in a laboratory or the doctor's office, measures plasma
glucose at timed intervals over a 3-hour period.
Gestational diabetes is diagnosed based on plasma glucose values
measured during the OGTT. Glucose levels are normally lower during
pregnancy, so the threshold values for diagnosis of diabetes in pregnancy
are lower. If a woman has two plasma glucose values meeting or exceeding
any of the following numbers, she has gestational diabetes: a fasting
plasma glucose level of 95 mg/dL, a 1-hour level of 180 mg/dL, a 2-hour
level of 155 mg/dL, or a 3-hour level of 140 mg/dL.
(Source: excerpt from Diabetes Overview: NIDDK)
If you are 45 years old or older, you need to get tested for diabetes,
even if you do not have any of the risk
factors listed below. If you are younger than 45 and have one or more
risk factors, you should also get tested. Ask your doctor for a fasting
blood glucose test. The results of this blood test will tell your doctor
how much glucose is in your blood. Your doctor may ask you to have the
test twice.
Even if your blood glucose level is normal and you have no risk
factors, if you are over 45, you may need to remind your doctor to check
your blood glucose again in 3 years. If you have at least one of the risk
factors below, have your blood checked more frequently. (Source: excerpt from Am I at Risk for Type 2 Diabetes: NIDDK)
A Lower Number To Diagnose Diabetes The expert committee also
recommended a lower fasting plasma glucose (FPG) value to diagnose
diabetes. The new FPG value is 126 milligrams per deciliter (mg/dL) or
greater, rather than 140 mg/dL or greater. This recommendation was based
on a review of the results of more than 15 years of research. This
research showed that a fasting blood glucose of 126 mg/dL or greater is
associated with an increased risk of diabetes complications affecting the
eyes, nerves, and kidneys. When diagnosis was based on a blood glucose
value of 140 mg/dL or greater, these complications often developed before
the diagnosis of diabetes. The experts believe that earlier diagnosis and
treatment can prevent or delay the costly and burdensome complications of
diabetes.
The prior criteria for diagnosing diabetes relied heavily on performing
an oral glucose tolerance test (OGTT). In this test, the person must come
in fasting, drink a glucose syrup, and have a blood sample taken 2 hours
later. This complicated procedure made detection and diagnosis of diabetes
a difficult and cumbersome process, and the expert committee recommended
that it be eliminated from clinical use. The change to using fasting
plasma glucose for determining the presence of diabetes will make
detection and diagnosis of diabetes more routine. The fasting value can be
easily obtained during routine physician visits, in clinics at the place
of employment, and other situations. Currently, about 5 to 6 million
adults in the United States have diabetes but do not know it. The simpler
testing method of measuring fasting glucose should help identify these
people so they can benefit from treatment sooner. (Source: excerpt from Diabetes Diagnosis: NIDDK)
The committee states that diabetes can be detected
by any of three positive tests. To confirm the diagnosis, there must be a
second positive test on a different day.
-
A casual plasma glucose level (taken at any time of day) of 200 mg/dL
or greater when the symptoms of diabetes are present.
-
A fasting plasma glucose value of 126 mg/dL or greater.
-
An OGTT value in the blood of 200 mg/dL or greater measured at the
2-hour interval.
As mentioned above, the committee
recommended that the OGTT not be used. (Source: excerpt from
Diabetes Diagnosis: NIDDK)
The new diagnostic criteria for diabetes include
the following changes:
- The routine diagnostic test for diabetes is now a fasting plasma
glucose test rather than the previously recommended oral glucose
tolerance test. (However, in certain clinical circumstances, physicians
may still choose to perform the oral glucose tolerance test.)
- A confirmed** fasting plasma glucose value of greater than or equal
to 126 milligrams/deciliter (mg/dL) indicates a diagnosis of diabetes.
Previously, a value of greater than or equal to 140 mg/dL had been
required for diagnosis.
- In the presence of symptoms of diabetes, a confirmed** nonfasting
plasma glucose value of greater than or equal to 200 mg/dL indicates a
diagnosis of diabetes.
- When a doctor chooses to perform an oral glucose tolerance test (by
administering 75 grams of anhydrous glucose dissolved in water, in
accordance with World Health Organization standards, and then measuring
the plasma glucose concentration 2 hours later), a confirmed** glucose
value of greater than or equal to 200 mg/dL indicates a diagnosis of
diabetes.
In pregnant women, different requirements are used to
identify the presence of gestational diabetes.
*For further information about the new diagnostic
criteria for diabetes, please see the "Report of the Expert Committee on
the Diagnosis and Classification of Diabetes Mellitus," in the References.
**Except in certain specified circumstances, abnormal tests must be
confirmed by repeat testing on another day.
(Source: excerpt from Diabetes Statistics in the United States: NIDDK)
One other number to know is the result of a blood test your doctor does
called hemoglobin A-1-c (HE-muh-glow-bin A-1-C) or glycated
hemoglobin (GLY-kay-ted HE-muh-glow-bin). It shows your blood
glucose control during the past 2 to 3 months. For most people, a good
hemoglobin A-1-c is 7 percent. (Source: excerpt from Medicines for People With Diabetes: NIDDK)
Each year make sure your doctor tests a sample of your urine to see if
your kidneys are leaking albumin. If your kidneys are not leaking a lot of
albumin, ask your doctor to check your urine for even smaller amounts of
albumin. This is called microalbumin (MY-kro-al-BYOO-min).
(Source: excerpt from Keep your kidneys healthy: NIDDK)
Your doctor might test your blood to measure the amounts of
creatinine (kree-AT-ih-nin) and urea (yoo-REE-uh). These are waste
products your body makes. If your kidneys are not cleaning them out of
your blood, they can build up and make you sick.
Your doctor might also ask you to collect your urine in a large
container for a whole day or just overnight.
(Source: excerpt from Keep your kidneys healthy: NIDDK)
A diagnosis of diabetes can be confirmed by a series of tests that
might include:
-
A blood test that measures the glucose in your blood. A
blood glucose level of 200 milligrams per deciliter (mg/dL) or greater,
with symptoms, means that you have diabetes.
-
A blood test for glucose after you have fasted, called
fasting plasma glucose (FPG) value. An FPG value of 126 mg/dL or greater
means that you have diabetes.
-
A measurement of glucose in your blood through an oral
glucose tolerance test (OGTT). Although this test is no longer
recommended because it is cumbersome, some health care providers may
still use it. After fasting, you have to drink a glucose syrup and have
a blood sample taken 2 hours later. An OGTT value of 200 mg/dL or
greater means that you have diabetes.
(Source: excerpt from
Diabetes: NWHIC)
» Next page: Glossary
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