LED (Laju Endap Darah)

Protap TES LED. 

Cara Westergren

A. Pra analitik

Persiapan Penderita :
tidak memerlukan persiapan khusus

Persiapan sampel:
Darah vena dicampur dengan anti koagulan Natrium citrate 3,8 % dengan perbandingan 4:1 . Dapat juga dipakai darah EDTA yang diencerkan dengan NaCl 0,95 dengan perbandingan 4:1.

Prinsip :
Mengukur kecepatan sedimentasi sel eritrosit di dalam plasma. Satuannya mm / jam

Alat dan bahan :
a. Pipet Westergren
b. Rak untuk pipet Westergren
c. Natrium Citran 3,8 %


B. Analitik
Isi pipet westergren dengan darah yang telah diencerkan sampai garis tanda 0. pipet harus bersih dan kering. Letakan pipet pada rak dan perhatikan supaya posisi betul – betul tegak lurus pada suhu 18 – 250º C.
Jauhkan dari cahaya matahari dan getaran. Setelah tepat 1 ( satu ) jam, baca hasilnya dalam mm/jam

C. Pasca analitik
Nilai rujukan Laki – Laki : 0 – 15 mm / jam
Perempuan : 0 – 20 mm / jam

Sumber Kesalahan :
Kesalahan dalam persiapan penderita, pengambilan dan penyiapan bahan pemeriksaan.
Dalam suhu kamar pemeriksaan harus dilakukan dalam 2 jam pertama, apabila darah EDTA disimpan pada suhu 4º C pemeriksaan dapat ditunda selama 6 jam. Perhatikan agar pengenceran dan pencampuran darah dengan larutan antikoagulan dikerjakan dengan baik. Mencuci pipa westergren dapat dilakukan dengan cara membersihkannya dengan air, kemudian alcohol dan terakhir acetone. Cara lain adalah dengan membersihkan dengan air dan biarkan kering satu malam dalam posisi vertical. Tidak dianjurkan memakai larutan bichromat atau deterjen. Nilai normal pada umumnya berlaku untuk 18 – 25º C. Pada pemeriksaan pipet harus diletakan benar – benar posisi vertical.

(artikel dari beberapa sumber).



Article in English:

DISPETTE 2 MODIFIED WESTERGREN METHOD

PRINCIPLE

Erythrocyte Sedimentation Rate (ESR or Sed Rate) is a nonspecific screening test used to help diagnose conditions associated with acute and chronic inflammation, including infections, cancers, and autoimmune diseases. It is said to be nonspecific because increases do not tell the medical provider exactly where the inflammation is in the body or what is causing it, and also because it can be affected by other conditions besides inflammation. For this reason, ESR is typically used in conjunction with other tests.

Anticoagulated blood is drawn up into a tube of standardized dimensions and left in a vertical position for exactly one hour. After that period the point at which the red cells have separated and settled from the plasma is recorded by reading from the scale on the side of the tube.

The phenomenon of red cell sedimentation is only partly understood. Three definite phases have been identified in the sedimentation process. During the first, or Lag Phase (10 minutes), the red cells form a characteristic rouleaux pattern and sedimentation is generally slow. The rate accelerates in the second period, the Decantation Phase or precipitation phase. In the final or packing phase, the red cell aggregates pile up on the bottom of the tube or container; sedimentation slows down as a result of mutual interference of the closely packed aggregates.

The size of the rouleaux aggregates formed in the Lag Phase is the critical factor affecting the final result of the ESR. The rouleaux itself appears to e influenced mainly by certain plasma proteins including fibrinogen, IgM and alpha1-macroglobulin. Thoughts vary as to the accelerating and retarding properties of glycoproteins and albumin.

SPECIMEN REQUIREMENTS

1. Patient Preparation–N/A

2. Type–EDTA anticoagulated blood (1 to 2 mg EDTA/1ml blood).

3. Handling Conditions–The test should be set up within two hours after the blood sample is obtained (or 12 hours if the blood is kept at 4oC). Refrigerated blood must always first be brought to room temperature for testing. If room temperature EDTA blood is being used the blood should be placed on the blood rocker for 10-15 minutes to allow adequate mixing of the blood cells.

MATERIALS AND EQUIPMENT

1. Equipment
Dispette tube holder w/leveling bubble
Timer

2. Materials
Dispette 2 reservoir pre-filled with bacteriostatic saline.

NOTE: Whole blood must be diluted as undiluted blood collected in EDTA gives inaccurate and poorly reproducible results – 2 ml whole blood diluted with 0.2 ml saline.

Dispette autozero tube with constant 2.55 ml internal diameter (complies with NCLLS guidelines.)
Plastic disposable pipette

3. Preparation–N/A

4. Performance Parameters–NA

5. Storage Requirements–Store reservoirs at room temperature.

CALIBRATION–N/A

QUALITY CONTROL

1. Test is performed in duplicate and results must agree within 10%. If not, repeat test.

2. Rack is kept in level position on counter free from vibrations.

3. Care is taken to avoid sources of error.

PROCEDURE

STANDARD PRECAUTION: Patient specimens and all materials coming into contact with them should be handled as if capable of transmitting infections and disposed of with proper precautions. Gloves should be worn when handling all specimens.

1. Anticoagulated specimens must be checked with two applicator sticks to ensure no clots are present. If clots are present the specimen is unsatisfactory. Blood should be mixed well and at room temperature.

2. Hold clear filling reservoir by flared section and shake downwards with a flick of the wrist to force saline to the bottom of the reservoir. Keep upright and remove cap.

3. Add 1 mL well mixed EDTA treated whole blood to the filling line level, either from a transfer pipette or directly from the blood tube. Ensure that the blood mixture reaches the filling line.

4. Replace cap securely.

5. Gently mix, mechanically or manually, by inversion. A minimum of 8 inversions is recommended.

6. Ensure that all the blood returns to the bottom section of the reservoir.

7. While holding filing reservoir firmly with one hand, and the Dispette tube with the other hand positioned at the 180 mm mark, penetrate the cap membrane and stop.

8. Gently continue inserting the Dispette tube to the bottom of the reservoir. Ensure that the blood level, on rising up the Dispette tube, reaches to or beyond the grommet at the zero level. When the Dispette is fully inserted, any extra blood will be accommodated by the plugged overflow-chamber.

9. Place the full Dispette assembly in a leveled plastic or metal stand. Ensure that the Dispette tube is at 90o degrees + one degree to the horizontal. Readings are recorded in millimeters at exactly one hour after setting upright.

10. Pipette 1 ml. blood into the pre-filled reservoir up to the fill line.

11. At the end of one hour, read the sedimentation rate directly from the tube in mm. Record results and discard the Dispette appropriately.

 
CALCULATION

Result is read directly from the tube. The distance from the bottom of the surface meniscus to the top of the column of red cells is recorded in millimeters per hour (mm/hr). If demarcation is hazy, level is taken where full density is first apparent.

REPORTING RESULTS
Normal Values

Males 0–9 mm/hr
Females 0–20 mm/hr

Results are handwritten on laboratory requisition form. Unusual or abnormal results should be brought to the attention of the medical provider.

PROCEDURE NOTES

Sources of error

1. Failure to mix blood properly, or clots in tube. Hemolysis may also modify sedimentation.

2. Failure to perform test within two hours after blood is collected - twelve hours if kept at 40o C.

3. Rack not on level surface. Sedimentation is accelerated if tube is not vertical. An angle of even 3o from vertical may accelerate the ESR by as much as 30 %. The test should be performed away from drafts or vibrations.

4. Temperature variation. The rate is consistent at 20o C and little variation from 22 to 27o C (65-72oF). Otherwise, tube should be in constant temperature water bath. Refrigerated blood should be allowed to reach room temperature before test is set up.

5. Vibration can seriously affect the ESR. Ensure that the bench top is not in contact with machinery (especially centrifuges), or subject to knocks.

6. Do not pick up the stand to read results as this will affect other tests in progress. Bring the eye to the level of the top of the red cells to read accurately from the scale.

7. Ensure you read the result at exactly 1 hour from when you set up the tube in the rack: remember the cells will go on settling after the first hour and results read at 75 minutes will usually be higher than those read at 60 minutes. Use a laboratory timer or alarm to remind yourself to read the results at the correct time

LIMITATIONS

Anemia is responsible for an accelerated ESR as the change in erythrocytes-plasma ratio favors rouleaux formation and therefore more rapid settling. Davidsohn and Henry state that the present tendency is to recognize that the value of the ESR is extremely limited in the presence if anemia and that a correction for the anemia is of questionable value.

CLINICAL SIGNIFICANCE

1. In general, the ESR is increased in all acute, general infections; in localized, acute, inflammatory conditions, variations in the ESR depend on the nature and severity of the process.

2. On occasion, the ESR may be increased where clinical and laboratory evaluation yield negative results. This should nonetheless be regarded as a sign of disease until such time as the medical provider is fully satisfied that the patient is perfectly well.

3. The ESR may be useful to differentiate organic disease from functional disorders, or as a guide to the progress of diseases such as rheumatic carditis, rheumatoid arthritis, and certain malignancies, including Hodgkin’s disease.

REFERENCE

1. Ulster Scientific Dispette 2 Modified Westergren ESR product insert.

2. Davidsohn, 1, Henry JB (Eds): Todd-Sanford Clinical Diagnosis by Laboratory Methods. ed. 15, Philadelphia, W.B. Saunders Co. pp. 134-135.

3. Hardison, C. The Sedimentation Rate. JAMA 1968: 204, 165.

4. National Committee for Clinical laboratory Standards. Methods for the Erythrocyte Sedimentation Rate (ESR) Test – Third Edition; Approved Standard, NCCLS document H2-A3. Villanova, Pennsylvania, NCCLS, 1993.

5. Pincherie & Shanks. Value of the ESR as a Screening Test. Br. J. Prev. Soc. Med. 1967: 21, 133-138.

6. International Congress for Standardization in Hematology (I.C.S.H.) Recommendations for Measurement of Erythrocyte Sedimentation rate. J Clin Path 1993: 46, 198 – 203.

7. Manley, R. The Effect of Room Temperature on ESR and its Correction. J Clin Path 1957: 10, 354.