Serologic tests are blood tests that look for antibodies in your blood. They can involve a number of laboratory techniques. Different types of serologic tests are used to diagnose various disease conditions.
All the serological tests have one thing in common. They all focus on proteins made by the immune system. This system of our body helps to keep you healthy by destroying foreign invaders that can make you ill. The process for having the test is the same regardless of which technique the laboratory uses during serologic testing. There are three types of serological test.

• An agglutination assay shows whether antibodies exposed to certain antigens will cause particle clumping.
• A precipitation test shows whether the antigens are similar by measuring for the presence of antibody in body fluids.
• The Western blot test identifies the presence of antimicrobial antibodies in your blood by their reaction with target antigens
• Neutralization test: The serum virus neutralization(SVN) assay is a serological test used to detect the presence and magnitude of functional systemic antibodies that prevent infectivity of a virus.
• Hemagglutinin-Inhibition test: The hemagglutination inhibition(HI) assay is used to titrate the antibody response to a viral infection.
• Flocculation test: Flocculation testsare designed for antibody detection and are based on the interaction of soluble antigens with antibodies, producing a precipitate of fine particles that can be seen with the naked eye

Test result Interpretation :

Normal test results

Antibodies are produced in response to antigens. If testing shows no antibodies, it indicates there is no infection. Results that show there are no antibodies in the blood sample are normal.

Abnormal test results

Antibodies in the blood sample often mean our body has an immune system response to an antigen from either current or past exposure to a disease or foreign protein.

The presence of certain types of antibodies can also mean that you’re immune to one or more antigen. This means that future exposure to the antigen or antigens won’t result in illness.

The aim is to get a specimen (sample) of urine from the middle of your bladder. Urine is normally sterile (no bacteria present). If bacteria are found in the sample, it means that the urine is infected.
A midstream sample is best as the first bit of urine that you pass may be contaminated with bacteria from the skin. A urine bottle will be provided by the centre.

Prior to collecting the midstream urine specimen:

• Wash hands and genitals.
• Do not open the sterile bottle until you are ready to take the sample.
• Avoid touching any part of your genitals with the bottle, as this may cause contamination.
• Pass some urine into the toilet and then without stopping the flow of urine, catch some urine in the sterile bottle up the indicated mark (the attending nurse will mark the urine bottle).
• Finish off passing the rest of your urine into toilet.
• If there is not enough urine collected any amount is better than none.
• Put the cap back on the container when you are finished.

24 hr urine collection:

To ensure accurate test results, the following  instructions below should be followed carefully. Some 24 hour urine tests require an additive in the container. It is recommended to consult  physician prior to the test to make sure you have the correct container.

Collecting the specimen:

• Decide a time to start the test (eg.8am)
• Labelling of the container with full name, date of birth  the container with your full name, date of birth and the date and time you start the collection
• Empty your bladder at this time and DISCARD THIS URINE.
• From now on ALL URINE PASSED in the next 24 hours should be collected in a container and MUST be transferred to the large bottle. Keep the container in a cool place (do not refrigerate) in an upright position with the lid firmly secured at all time
• 24 hours after the commencement time (eg.8am the next morning) empty your bladder and place this urine into the battle. Your specimen is now complete
• Write the date and time that you completed the sample on the label.
• Deliver the container back to your physician

For 24 hr Creatinine Clearance: This test is used to measure kidney function and requires a blood test to be taken within 48 hours of the urine being collected. It is preferable to have the blood test when you deliver the completed urine specimen.

This test detects the presence of blood in the faeces. To ensure accurate test results, following instruction should be followed carefully.

For this test, you will need to collect faeces samples each day for three days in a row OR a sample from each of three consecutive bowel movements. The containers to use are tubes with a dipstick attached to the top.

• Label the jars with  first name, family name, date of collection and time of collection.
• Ensure no urine comes into contact with the faeces sample
• Pass urine into the toilet first if necessary, then place a clean plastic container into the toilet bowl to catch the faeces

• Using the dipstick, dip the stick into the faeces at 4-5 random sites, allowing the faeces to cover the end. Then carefully place the stick back into the tube

• Screw the lid on securely

Important instructions:

Do not collect samples during, or until three days after a menstrual period.

Avoid taking Aspirin or other non-steroidal anti-inflammatory drugs for seven days before the collection. (Please consult your physician first before withholding any medication).

Prior to this test, try to maintain a well-balanced diet of fruit and vegetables.

Before collection, brush your teeth, rinse your mouth well and gargle with water to reduce contamination with food particles.

(for micro & culture) collect 1 sample

• Label the sputum jar with your first name, family name, date of birth, time of collection and date of collection.
• Sputum should be produced from the base of the lungs, usually through a deep cough. It is important to note that Sputum is usually white, yellow or green in color. Saliva, in contrast, is often clear and colorless. Saliva is not acceptable in this test and will result in a re-collection if submitted.
• Spit the sputum directly into the jar provided.
• It is sometimes easier to perform this first thing in the morning.
• Close the lid tightly and return to your physician .

(for cytology) collect 2 samples (1 sample per day, for 2 days)

• Collect 3 jars from laboratory. These jars might have preservative liquid inside.
• Label the sputum jars with your first name, family name, time of collection and date of collection.
• Sputum should be produced from the base of the lungs, usually through a deep cough. It is important to note that Sputum is usually white, yellow or green in colour. Saliva, in contrast, is often clear and colourless. Saliva is not acceptable in this test and will result in a re-collection if submitted.
• Spit the sputum directly into the jar.
• Close the lid tightly

Adrenocorticotropic hormone (ACTH) is a hormone produced in the anterior, or front, pituitary gland in the brain. The function of ACTH is to regulate levels of the steroid hormone cortisol, which released from the adrenal gland. An ACTH test measures the levels of both ACTH and cortisol in the blood and helps  to detect diseases that are associated with too much or too little cortisol in the body. Possible causes of these diseases include:

• a pituitary or adrenal malfunction
• a pituitary tumour
• an adrenal tumour
• a lung tumour

Patient preparation

For the 12 hours before specimen collection it is  not recommended to take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Sample should be EDTA PLASMA.

Collection Instructions:

• Morning (6 a.m.-10:30 a.m.) specimen is desirable.
• Centrifuge at refrigerated temperature within 2 hours and plasma should be immediately separated from cells.
• Freeze plasma sample immediately.

A high level of ACTH may be a sign of:

• Addison’s disease
• Adrenal hyperplasia
• Cushing’s disease
• an ectopic tumour that produces ACTH adrenoleukodystrophy, which is very rare
• Nelson’s syndrome, which is very rare

A low level of ACTH may be a sign of:

• Adrenal tumour
• Exogenous Cushing’s syndrome
• Hypopituitarism

A cortisol level test uses a blood sample to measure the level of cortisol present in your blood.

Cortisol is a steroid hormone released by the adrenal glands. The adrenal glands sit on top of your kidneys. A cortisol level test may also be called a serum cortisol test. Cortisol is the main hormone involved in stress and the fight-or-flight response. This is a natural and protective response to a perceived threat or danger. Increased levels of cortisol result in a burst of new energy and strength.

Why cortisol test is done ?

The cortisol level test is used to check if your cortisol production levels are either too high or too low. There are certain diseases, such as Addison’s disease and Cushing’s disease, which affect the amount of cortisol produced by adrenal glands. The test is used in the diagnosis of these diseases and as a way to assess the functioning of the adrenal and pituitary glands.

Cortisol plays a role in several systems in the body. These systems include:

• stress responses
• immune system
• nervous system
• circulatory system
• skeletal system
• the breakdown of proteins, fats, and carbohydrates

Preparation for the test

There are certain drugs that affect cortisol levels.

Cortisol levels are sometimes increased by:

drugs containing oestrogen synthetic glucocorticoids, such as prednisone pregnancy.

Cortisol levels are sometimes decreased by:

• drugs containing androgens
• phenytoin

Cortisol levels can also be affected by physical stress, emotional stress, and illness. This is due to the increased release of ACTH by the pituitary gland during the normal stress response.

Semen is composed of spermatozoa suspended in seminal fluid (plasma). The function of the seminal fluid is to provide nutrition and volume for conveying the spermatozoa to the endocervical mucus. Male infertility can be affected by a number of causes. Chief among these is a decrease in the number of viable sperm. Other causes include sperm with abnormal morphology and abnormalities of the seminal fluid.

Semen analysis test is done for determining male infertility status.

Sample collection /Pre analytical requirements

• Patients is provided with a laboratory grade specimen container which is fit for purpose.
• The patient should be on abstinence for 3 days and no more than 7 days prior to collection.
• If the sample is to be collected by masturbation use of lubricant is not preferred.
• Use of condom for sample collection is not recommended. Because condoms may contain lubricants, latex which may effect the viability of sperm.
• The specimen should be maintained at a temperature between 20°C and 37°C during transportation to the laboratory.
• The specimen should be delivered to the laboratory for analysis within one hour of collection.
• The information from the patient which may be relevant to the interpretation of

analytical results should be recorded.

(a) time of collection

(b) the number of days of ejaculatory abstinence

(c) storage conditions between collection and receipt into the laboratory

(d) whether any of the ejaculate was lost during collection.

Vanillylmandelic acid (VMA) is one of the breakdown products (metabolites) of epinephrine (adrenaline) and norepinephrine. Epinephrine and norepinephrine belong to a group of similar hormones called catecholamines. This test measures the amount of VMA that is passed into the urine, typically over a 24-hour period, to detect excess epinephrine and norepinephrine. It is used to detect tumors called neuroblastomas and other neuroendocrine tumors.

It also helps  to monitor the effectiveness of treatment in curing neuroblastoma. This test is done if the symptoms like having  lump in the abdomen (abdominal mass), bruising around the eyes, trouble walking, or bone pain are observed. It is also done if one have symptoms of increased catecholamine release, such as persistent or periodic high blood pressure, severe headaches, rapid heart rate, and sweating etc

Patient preparation

Certain foods can increase urinary catecholamines, including coffee, tea, bananas, chocolate, cocoa, citrus fruits, and vanilla. Therefore these foods should be avoided for several days prior to the test. Acute stress and vigorous exercise may also affect the test results. Similarly there are some drugs which may also effect the results of the tests. Caffeine, acetaminophen, levodopa, lithium ,aminophylline, chloralhydrate, clonidine, disulfiram, erythromycin, insulin, Methenamine, methyldopa, nicotinic acid (large doses), quinidine, tetracyclines, nitroglycerin may increase the Urine VMA values. Likewise guanethidine, imipramine, MAO inhibitors, phenothiazines, salicylates, reserpine may decrease the Urine VMA. Therefore these drugs and diet should be avoided prior to the test.

Sample collection

For a 24-hour urine collection, all of the urine produced during a 24-hour period should be saved. It is important that the sample should be refrigerated during this time period. A single urine sample is also collected for a random urine test.

The reason to collect urine over a 24-hour period is because the amount of VMA released in the urine changes during the course of a day. By collecting all urine for 24 hours, the amount of VMA measured can be averaged over the entire day and will give a better indication of whether levels are increased or not.

The glucose challenge test measures your body’s response to sugar (glucose). The glucose challenge test is done during pregnancy to screen for gestational diabetes that develops during pregnancy.

The test is generally done between weeks 24 and 28 of pregnancy.

However, it can be done as early as first prenatal visit if you’re at high risk of gestational diabetes due to obesity, a personal history of gestational diabetes, a family history of diabetes or other factors.

Most women who have gestational diabetes deliver healthy babies. However, without careful management, gestational diabetes can lead to various pregnancy complications, such as excess fetal growth — which might increase the risk  of birth injuries or prompt a C-section delivery.

Reason Why It is Conducted

The test is usually done to check for gestational diabetes in pregnant women. If a woman had developed gestational diabetes in a previous pregnancy, the test is conducted for every subsequent pregnancy. Women who are overweight at the time of getting pregnant are also recommended to have this test conducted. Women with polycystic ovarian syndrome should also get this test done because the chances of developing diabetes are quite high in this case.

Preparation

No elaborate preparations are needed for the test. However, it is recommended that nothing should be eaten about eight hours prior to the test. Just before the test, you will have to drink a glucose solution quickly. About one hour later,  blood is taken for the test. The one hour gap is taken because the glucose levels peak one hour after consumption of glucose and then begin to drop subsequently. This is only the first part. If the glucose challenge test results show that you have gestational diabetes, further diagnosis is done ie recommended for GTT test.

The glucose liquid is usually extremely sweet and you may begin to feel sick after drinking it. A lot of people have been known to vomit just after they have consumed the liquid. However, if vomiting happens, the test should be taken on another day again.

Though normal values differ, the usual normal range when 50 grams of glucose is taken and the screening test is done one hour later is lower than 140 mg/dL or 7.8 mmol/L; anything greater than that requires a further diagnostic test

The oral glucose tolerance test (OGTT), also known as the glucose tolerance test, gauges the body’s ability to metabolize sugar (glucose) and clear it from the bloodstream. The OGTT can be used to diagnose diabetes 1 , gestational diabetes (diabetes during pregnancy), or prediabetes (elevated blood sugar predictive of type 2 diabetes).

Types of glucose Tolerance Test

Illustration by Emily Roberts, Verywell

Patient Preparation

• Test involves fasting overnight (from 8 to 16 hours) and participating normally in activities of daily living.
• The individual should eat and drink as they normally do prior to the test.
• The morning of the test, the person should not consume caffeine or smoke.

Evaluation of the test.

• Normal response: A person is said to have a normal response when the two-hour glucose level is less than 140 mg/dl, and all values between 0 and 2 hours are less than 200 mg/dl.
• Impaired glucose tolerance (IGT): A person is said to have impaired glucose tolerance when the fasting plasma glucose is less than 126 mg/dl and the two-hour glucose level is between 140 and 199 mg/dl. This is sometimes referred to as “prediabetes” because people with IGT have a higher risk of developing diabetes.
• Diabetes: A person has diabetes when two diagnostic tests done on different days show that the blood glucose level is high. This means either the two-hour levels is greater than 200 mg/dl or the fasting glucose is noted as greater than 126 mg/dl. A glycosylated haemoglobin (HbA1c) level of 6.5% or more also supports a diagnosis of diabetes mellitus.
• Diabetes during pregnancy: A pregnant woman has diabetes if she has a fasting plasma glucose of over 92 mg/dl, or a two-hour glucose level greater than 153 mg/dl.