FAQs

General Questions
Yes, certain tests do need prior fasting. The most common ones are:

Lipid Profile – 12 Hours
Blood Sugar Fasting – 8 Hours
Insulin Fasting – 8 Hours
C Peptide Fasting – 8 Hours
Ultrasound – Whole abdomen, Upper abdomen
TMT
Common analyses which do not require fasting are:-

Kidney Function Test (Urea, Creatinine, Uric Acid, Electrolytes)
Liver Function Test (Bilirubin Total, Direct, SGOT, SGPT, Alkaline Phosphatase, GGTP)
Thyroid Function Test
HbA1c
Urine Culture
ECG
Bone Dexa
Though, it is always advisable to consult the laboratory expert and clarify in advance.
CT Scan Questions
CT scan uses x-rays to produce the images and for patient’s safety, the X-ray dose is kept to minimum for each scan. However, one should avoid having CT scan during pregnancy.

At the time of the scan, an injection of fluid is given into the vein in indivisual’s arm or head. The fluid assists to give clear images. Though the fluid (a dye) is completely free from any side effects, very occasionally, one can have an allergic reaction to the injection of contrast medium. This issue is usually faced by asthma patients. But, a point to note here is that the advantages of having a CT scan outdo the risk of contact to radiation, as the result obtained from the scan is worth it.

In the unlikely event, if a patient faces an allergic reaction, staffs working in the CT scanning are trained to manage the situation. Please note, before CT scan, one is required to fill the form that explains the risk involved in the whole procedure.

General Questions
Q. Is fasting necessary before certain tests? If yes, what are those tests and what should be the ideal duration of fasting?
Yes, certain tests do need prior fasting. The most common ones are:

Lipid Profile – 12 Hours
Blood Sugar Fasting – 8 Hours
Insulin Fasting – 8 Hours
C Peptide Fasting – 8 Hours
Ultrasound – Whole abdomen, Upper abdomen
TMT
Common analyses which do not require fasting are:-

Kidney Function Test (Urea, Creatinine, Uric Acid, Electrolytes)
Liver Function Test (Bilirubin Total, Direct, SGOT, SGPT, Alkaline Phosphatase, GGTP)
Thyroid Function Test
HbA1c
Urine Culture
ECG
Bone Dexa
Though, it is always advisable to consult the laboratory expert and clarify in advance.
CT Scans Questions
Q. Is CT scan safe?
Q. Do I have to do special preparations for my CT scan?
It entirely depends on which part of the body you want to be scanned. Probably you will be asked to remove your cloths and sometimes, all the metal objects like jewellery, and wear a hospital gown instead. In some cases, you may also be asked to drink contrast liquid or have contrast injected into the vein. If your test involves a contrasting medium, your doctor may instruct you to fast for a few hours prior the test.
Talking about medicines, you can have your medicines before the CT scan, until and unless you are a diabetic patient. In that case, you are advised not to take any medicine. However, you should talk to the physicians before the test for the do’s and don’ts.
X-rays Questions
X-ray is a quick and simple imaging test and you will feel nothing at all during your X-ray.
Well, most bone X-rays require no special preparations. At the max, you will be asked to remove your clothes and sometimes, all the metal objects like jewellery, and wear a hospital gown instead. As that may interfere with the imaging process.
There is so such study till now that states the minimum and maximum number of x-rays in a year or in a lifetime. Although, the amount of radiation that one receives from x-ray is too small to harm anybody.
Mammography Questions
A mammography, or mammogram, is an X-ray of the breast. It's a screening tool used to detect and diagnose breast cancer. Together with regular clinical exams and monthly breast self-examinations, mammograms are a key element in the early diagnosis of breast cancer.
Study shows that 8 out of 10 breast cancer patients are cured with early detection. So yes, it can save life.
Almost all women should perform a self-exam by touching their breasts every month.
Women between the age 35-40 should go for it every year
Women above the age 40 or 50 should for it twice a year.
If your mammogram is normal, it is really good. Although, you should make it a regular practice to stay updated about your breasts health.
There is nothing to panic on if it comes abnormal. An abnormal mammogram does not always means it is cancer. But, for the doctor to be sure, you will have to go through similar tests. In some cases, you may also be referred to a breast specialist.
After the age of 35, the effect of radiation decreases and so there is nothing to worry about. The only concern is pregnancy. Pregnant women should avoid going for this test.
Sonomammography (ultrasound of breast) is a non-invasive process performed to examine the breasts and the blood flow to areas within. This test enables quick visualization of the breast tissue. It is often performed along with mammography (x-ray of breast tissue) to study a mass or a lump.
If that is the case, the person is at a high risk and should start doing mammography test regularly 10 to 15 years earlier than the age at which the relative got breast cancer. The chances are 5-15% if it is a first degree family member mainly on the maternal side.
Ultra sound-Sonography Questions
Pregnancy or pelvic ultrasound: A full bladder helps to enhance the ultrasound image of the pelvic organs. Therefore, you need to drink ample amount of water before the test i.e about 8 to 10 glasses. Also, do not go to the washroom before that because If the bladder is not full at the time of examination, the test may not be completed.

Abdominal Ultrasound : You need to fast for 8-12 hours prior to your abdominal ultrasound test. Getting a clear picture of the aorta and pancreas becomes difficult with food and liquid present in the stomach. However, it is always better to get the advice from the physician if you are on medications.

Renal Ultrasound: Drink 3-4 glasses of water before the test. You must be finished drinking the water before the exam start. Do not go to washroom until your test is done and hold your urine for accurate results.
Ultrasound exam has no after effect on an individual. You won’t feel any uneasiness or discomfort and you can begin again with your normal routine, diet and work as well.
Radiography and sonography, both are important technologies in medical diagnosis which helps to draw images from the inside of the body parts and tissues. Though both are used for the same purpose, there is still difference between the two.

Radiology uses radiations (x-rays) to produce images whereas Sonography uses ultra sound waves to produce images. Hence, they differ in their imaging system. In radiography, ionizing electromagnetic rays are used to produce images of the body parts whereas, in sonography, the assistant applies an ultra sound on the skin and send ultra sound waves inside the body by a probe.
3D and 4D scan Questions
3-Dimensional ultrasound and 4-Dimensional ultrasound are obstetric ultrasound methods that are performed to give clearer insights into the developing fetus than the traditional sonography. These methods are not necessary but performed only when the patients are interested. These tests are also suggested when doctors suspect some anomalies or birth defect in a child.
If you decide to have this test, the best time for 3D or 4D scan is when you're between 26 weeks - 30 weeks pregnant.
There is no current, reliable evidence that ultrasound is harmful. Ultrasound scans are generally considered to be safe if they are administered for medical reasons and by a qualified healthcare provider.

Source:
https://www.pampers.com/en-us/pregnancy/healthy-pregnancy/article/3d-4d-ultrasound-scans
The difference between 2D, 3D and 4D scan lies mostly in their scanning mechanism. The 2D and 3D scan shows only the external features while a 4D scan can show the baby’s internal organ as well. A 3D scan will show clear images of the baby like a photograph while the 2D scan has grey blurry lines that will show the baby’s movement. On the other hand, The 4D scan shows clear movements of the baby where one can see the facial expressions, body movements, shape of the nose, mouth, eyes etc.
Colour Doppler Test Questions
A Doppler ultrasound is a non-invasive test that can be performed to approximate the blood flow through the blood vessels by bouncing high-frequency ultrasound waves off circulating red blood cells. A regular ultrasound also uses sound waves to produce images, but it can't show blood flow.
Even if the doctor has suggested you Doppler test during the pregnancy, there is nothing to worry about. You don’t have to panic as the test is just to check the issues with you and the baby. It assists in confirming the fetal heartbeat, growth of the pregnancy, position of the umbilical cord, placenta, position of the baby and general progress.
There is a huge difference between the two.
A regular ultrasound can’t show blood flow but Colour doppler test can. It is a high-tech diagnostic test that can measure your blood flow and blood pressure by bouncing high frequency sound waves off red blood cells.
As such there are no specific preparations required for this test. But if you are a smoker, then you have to make sure that you do not smoke few hours before the test as smoking narrows down the blood vessels and you may not get accurate results.