Lakhasly

The study of chromosomes using traditional cytogenetic techniques requires cells that are actively dividing.Overview of cell culture and harvest Culture initiation -> Culture maintenance -> Cell harvest o Sterility Living cells o Arrest division o o Optimal temperature Sterility o Swell cells o o Optimal pH Proper growth medium o Fix cells o o Optimal humidity +- Mitotic stimulant o Prepare slide o o Optimal time interval Microbial inhibitors o Stain/band o The most critical requirement is that living cells capable of cell division be received by the laboratory.Specimens that contain spontaneously proliferating cells include bone marrow, lymph nodes, solid tumors tissue biopsies, amniotic fl uids, and chorionic villi.Specimen Collection and Handling Sample Requirements Peripheral Blood Specimens Peripheral blood samples should be collected in sterile syringes or vacuum tubes containing preservative-free sodium heparin.Metaphase chromosomes can be obtained from specimens that contain spontaneously dividing cells or ones that are cultured and chemically induced to divide in vitro .Specimen containers must be sterile and must be labeled with the patient's name and a second identifi er. The laboratory may reject specimens that are improperly labeled or unlabeled.If there are not enough naturally dividing cells for a chromosome analysis, these specimen types may also be cultured in the laboratory without the aid of mitotic stimulants.The choice of specimen for chromosome analysis depends on clinical indications and whether the diagnosis is prenatal or postnatal.The manner in which the sample is collected and subsequently handled will greatly in fl uence whether or not the cells will grow and divide, and the quality of the resulting metaphases.The individual details of culture initiation, maintenance, and cell harvest vary somewhat for the different sample types; however, the general steps and requirements are similar.Chromosomes are individually distinguishable under the light microscope only during cell division and are best examined during metaphase.Bone marrow aspirates should be collected in sterile syringes or vacuumIt is not always practicable or possible to obtain a new sample, and in such cases, the laboratory should attempt to salvage the original specimen.Bone Marrow Aspirates The collection requirements for bone marrow samples are essentially the same as for peripheral blood.Peripheral blood lymphocytes usually require the addition of a mitotic stimulant.Vacuum tubes should be discarded if outdated.Temperature extremes must be avoided if samples are transported or stored.These are summarized below .

The study of chromosomes using traditional cytogenetic techniques requires cells that are actively dividing. Chromosomes
are individually distinguishable under the light microscope
only during cell division and are best examined during metaphase. Metaphase chromosomes can be obtained from specimens that contain spontaneously dividing cells or ones that
are cultured and chemically induced to divide in vitro .
Specimens that contain spontaneously proliferating cells
include bone marrow, lymph nodes, solid tumors tissue biopsies, amniotic fl uids, and chorionic villi. If there are not enough
naturally dividing cells for a chromosome analysis, these specimen types may also be cultured in the laboratory without the
aid of mitotic stimulants. Peripheral blood lymphocytes usually require the addition of a mitotic stimulant. The choice of
specimen for chromosome analysis depends on clinical indications and whether the diagnosis is prenatal or postnatal.
The individual details of culture initiation, maintenance,
and cell harvest vary somewhat for the different sample
types; however, the general steps and requirements are similar. These are summarized below .
Overview of cell culture and harvest
Culture initiation → Culture maintenance → Cell harvest
• Sterility Living cells • Arrest division •
• Optimal temperature Sterility • Swell cells •
• Optimal pH Proper growth medium • Fix cells •
• Optimal humidity ± Mitotic stimulant • Prepare slide •
• Optimal time interval Microbial inhibitors • Stain/band •
The most critical requirement is that living cells capable
of cell division be received by the laboratory. The manner in
which the sample is collected and subsequently handled will
greatly in fl uence whether or not the cells will grow and
divide, and the quality of the resulting metaphases. Specimen
containers must be sterile and must be labeled with the
patient’s name and a second identifi er. The laboratory may
reject specimens that are improperly labeled or unlabeled.
Specimen Collection and Handling
Sample Requirements
Peripheral Blood Specimens
Peripheral blood samples should be collected in sterile
syringes or vacuum tubes containing preservative-free
sodium heparin. Vacuum tubes should be discarded if outdated. Peripheral blood cultures can be initiated several days
after the blood is drawn; however, for best results, blood
samples should be set up within 24 h of collection.
Temperature extremes must be avoided if samples are transported or stored. Specimens should be kept at room temperature or refrigerated above 4°C until they can be processed.
Culture medium is sometimes added to small blood samples,
as these have a tendency to dry up, especially if collected in
large containers.
A repeat sample should be requested if these requirements
are not met (e.g., the sample is received clotted, on ice, more
than 24 h old). It is not always practicable or possible to
obtain a new sample, and in such cases, the laboratory should
attempt to salvage the original specimen. There may be
enough viable cells for a cytogenetic analysis, though the
number and quality of cells may be compromised.
Bone Marrow Aspirates
The collection requirements for bone marrow samples are
essentially the same as for peripheral blood. Bone marrow
aspirates should be collected in sterile syringes or vacuum