Specimen Collection & Handling-Chemical Pathology

Ammonia

1. Please notify the laboratory prior to sample collection for analyzer preparation.

2. Collect sample using EDTA tube (purple cap) and immediately place on ice.

3. Urgent test must be sent in a separate container and NOT mix together with other routine test.

4. Send immediately to the laboratory within 15 minutes of collection. Delay may cause inaccurate test result.

5. For referring lab, separate plasma after centrifuge and freeze immediately at -20°C or lower. Please sent directly to Integrated Laboratory and Chemical Pathology Unit, Level 2, Twin Tower HQE.

Blood Gases

1. State time of arterial or venous puncture in the request form.

2. Use of commercial heparinized blood gas syringe is PREFERRED.

3. If unavailable, use a 1 mL disposable syringe and flush it with 5000 IU/mL heparin.

4. Draw 1 mL of blood.

5. Invert the syringe upward and expel all air bubbles.

6. Mix well by rolling the syringe between the palms to prevent clotting.

7. Place the stopper. Specimen received with needle will be REJECTED.

8. Keep the specimen embedded in crushed ice and send immediately for analysis (within 30 minutes). Specimens received exceeding this time frame may be subjected to rejection.

9. Request form for Blood Gases SHALL NOT be shared with other test request (e.g. Lactate). Please sent a separate form for other test request.

Lactate

1. Please notify the laboratory prior to sample collection for analyzer preparation.

2. Collect sample using Fluoride Oxalate (gray cap) and immediately placed on ice.

3. Urgent test must be sent in a separate container and NOT mix together with other routine test.

4. Send immediately to the laboratory.

5. For referring lab, separate plasma after centrifuge and freeze immediately at -20°C or lower. Please sent directly to Integrated Laboratory and Chemical Pathology Unit, Level 2, Twin Tower HQE.

Cerebrospinal Fluid (CSF)

1. Please notify the laboratory prior to sample collection for analyzer preparation.

2. Ensure specimen bottle is correctly labelled.

3. Send immediately to the laboratory following sample collection.

4. For referring lab, please sent directly to Integrated Laboratory and Chemical Pathology Unit, Level 2, Twin Tower HQE.

24-hour Urine Collection

1. 24-hour urine container which contains ± preservatives for the required test is available at the Integrated Laboratory counter and will be provided upon request with accompanying request form.

2. Advise patient not to discard preservatives in the container.

3. On the day of the collection, the first urine voided must be discarded.

4. Time of the first urine voided is start of the timing for the 24-hour urine collection.

5. Collect the second and subsequent voided urine for 24 hours into the container.

6. Advise patient not to void directly into the contains ± preservatives.

7. At the end of 24 hours, the last urine voided is collected.

8. If preservative is used, mix the contents thoroughly after each addition of urine.

9. Send the specimen immediately to the laboratory, otherwise store it at 4°C and deliver to the laboratory as soon as possible.

Creatinine Clearance Test

1. Collect a 24-hour urine specimen (as above).

2. Take 2 mLs of blood in plain tube (red/gold cap) for serum creatinine on the same day during the 24-hour urine collection duration.

3. Send both urine and blood specimens to the laboratory for analysis.

24-hour Urine Metanephrine (Referred test to Hospital Putrajaya)

1. Fill up PER-PAT 301 form with relevant clinical information and drug history. Specialist counter-signed is a must.

2. 24-hour urine container with 10 mL of 25% hydrochloric acid will be provided and the procedure of collection as above.

3. Patient needs to avoid:

   1. Food (please avoid for 24 hours prior to, and during urine collection): Chillies, nuts, caffeine (coffee/tea), chocolate/cocoa, eggplant, tomato, avocado, kiwi, fruit juices, pineapple, watermelon and banana.

   2. Drugs (please avoid for at least one week before specimen collection:

      1. Tricyclic antidepressants - e.g. Amitriptyline, Imipramine

      2. Antipsychotics - e.g. Clozapine, Olanzapine, Risperidone, Chlorpromazine

      3. Alpha-2-blockers - e.g. Phenoxybenzamine, Phentolamine

      4. Beta blockers - e.g. Labetolol, Atenolol, Metoprolol, Propanolol

      5. Monoamine oxidase inhibitors (MAOI) - e.g. Moclobamide, Phenelzine

      6. Sympathomimetic drugs - e.g. Pseudoephedrine, Phenylephrine, Dobutamine

      7. Recreational drugs - e.g. Amphetamines, Cocaine

      8. Others - Paracetamol, Levodopa

4. Avoid stress and vigorous exercise.

5. Request will be REJECTED if no specialist signature, no clear indication with incomplete clinical history and drug history, total specimen volume <750 mL for adult, specimen ph > 5 and leaking specimen.

ACTH (Synacthen) Stimulation Test

1. Withhold steroid treatment for 24 hours prior to the test (Patients treated with dexamethasone require at least 48 hours of steroid withdrawal) if appropriate.

2. Draw baseline sample of cortisol at 0 minute.

3. Give IM or IV 250ug ACTH.

4. Draw cortisol samples at 30 and 60 minutes.

5. Label specimens (including sample timing) accordingly and send to the lab immediately.

Dexamethasone Suppression Test

1. Overnight Dexamethasone Suppression Test (ODST) and Low Dose Dexamethasone Suppression Test (LDDST) are both screening tests for Cushing’s sybdrome.

2. For Overnight Dexamethasone Suppression Test (ODST):

   1. Take 1 mg Dexamethasone tablet with water at 11pm.

   2. Draw cortisol sample at 8am the next morning.

3. For Low Dose Dexamethasone Suppression Test (LDDST):

   1. Draw baseline cortisol sample at 8am on the first day of the test.

   2. Ask patient to take 0.5 mg Dexamethasone tablet stat and every 6-hourly for next 48 hour.

   3. Draw cortisol sample at 8am on the third day of the test.

Plasma Renin & Plasma Aldosterone - Aldosterone:Renin Ratio (Referred test to Hospital Putrajaya)

1. Fill up PER-PAT 301 form with relevant clinical information, drug history and latest potassium (K+) result. Specialist counter-signed is a must. Only single form is required for requesting Aldosterone:Renin Ratio.

2. Blood should be collected in between 8am to 10am, after patient has been out of bed for at least 2 hours and usually after they have been seated for 5 to 15 minutes. In cases which supine sample is taken, sample should be collected early in the morning.

3. State patient’s POSTURE clearly in the request form.

4. Collect samples into TWO EDTA tubes (purple cap) - one for Renin and another for Aldosterone. Minimum 3 mL blood sample required per tube - total 6 mL.

5. Blood samples should be sent rapidly (within 30 minutes) to the laboratory but NOT IN ICE.

6. Patient should be normally hydrated and has an adequate oral intake of sodium.

7. Avoid hypokalemia as it suppresses aldosterone secretion. Give potassium replacement (Slow Potassium tablets) to raise plasma potassium > 4.0 mmol/L.

8. Patient should STOP drugs that INTERFERE with renin-aldosterone axis for:

   1. 4 weeks: Spironolactone, Eplerenone, Amiloride, Triamterene, Potassium wasting diuretics, Licorice.

   2. 2 weeks: Angiotensin-converting enzyme inhibitors, Angiotensin receptor blockers, Renin inhibitors, Dihydropyridine calcium channel antagonists, Clonidine, Methyldopa, Beta blockers.

9. Drugs that DO NOT INTERFERE with the renin-aldosterone axis include: Prazosin, Verapamil, Hydralazine and Terazosin.

10. Checklist for Clinician (to be attached with request form):

    1. Adequate clinical history (with indication for Aldosterone:Renin Ratio)

    2. Drug history (including those that were stopped and duration)

    3. Latest serum Potassium (with date)

    4. Patient's posture (Supine/Upright)

    5. Requested by Specialist with official stamp

    6. Two (2) EDTA tubes (with 3 mL blood sample each tube)

    7. Transport at room temperature

Serum and Urine Protein Electrophoresis

1. Request for test can only be done by SPECIALIST. 

2. Request form (PER-PAT 301 form) must be filled with adequate clinical information (CRAB criteria - calcium level, renal profile, anemia and bone symptoms).

3. If test required within retesting interval of 3 months, consult Chemical Pathologist.

4. For screening of new cases, suggest to send paired serum sample with urine sample.

5. Rejection criteria:

   • Hemolysed serum sample

   • Plasma sample

   • Inadequate clinical history in the request form

   • No specialist sign and stamp (name of specialist consulted for non-specialist hospital).

6. For urine protein electrophoresis request, refer here for clinical indication.

7. Instructions for referring Lab Personnel (Scientific Officer/ MLT):

   • Ensure request form has specialist signature & stamp (or name of specialist consulted for non-specialist hospital).

   • Separate serum and transfer serum into the secondary tube.

   • Refrigerate sample (2 to 8 degree Celcius) as soon as possible.

Plasma Thiamine (Referred test to Makmal Kesihatan Awam Kebangsaan Sungai Buloh)

1. Fill up the MKA form.

2. Patient needs to fast for at least 12 to 14 hours. For infants, sample can be taken prior to next feeding. Plain water can be taken as needed.

3. Blood should be collected before breakfast in the morning and prior to any medication.

4. Blood sample collected into EDTA tube (purple cap) with a minimum amount of 3 mL. The sample should be sent in a close vial and LIGHT PROTECTED (cover sample tube with aluminium foil).

Urine Myoglobin (Referred test to Hospital Ampang)

1. Request form (PER-PAT 301 form) must be filled with adequate clinical information and counter-signed by specialist.

2. Request will be REJECTED if urine pH is less than 8, leakage or inadequate specimen volume, incomplete request form, no clinical indication and no counter-signed by specialist.

3. Instructions for Lab Personnnel (Scientific Officer/ MLT of referring laboratory):

1. 1. Ensure request form has specialist signature & stamp.

   2. Ensure the sample is a fresh urine sample with minimum volume of 10 mL.

   3. Sample should be collected in a universal container containing 200 mg of sodium bicarbonate (for every 10 mL of urine), resulting in a final concentration of 2%.

   4. Once sodium bicarbonate is added, verify and ensure that the specimen pH reaches or exceeds 8. Document it on request form. 

   5. Sample must be sent within 48 hours of collection.