Principles, Classification, and Clinical Laboratory Applications of Hematologic Cytochemical Staining

Hematologic cytochemical staining is a group of detection methods that, on the basis of cellular morphology, use specific chemical reactions to demonstrate intracellular enzymes, glycogen, lipids, iron granules, and other functional components. Its value is not to replace flow cytometric immunophenotyping, cytogenetics, or molecular testing, but to provide clues about cell lineage, differentiation stage, and functional status in the preliminary differentiation of bone marrow smears, peripheral blood smears, and hematologic diseases.

Keywords: hematologic cytochemical staining; bone marrow smear; peripheral blood smear; peroxidase staining; Sudan Black B staining; nonspecific esterase staining; specific esterase staining; PAS staining; neutrophil alkaline phosphatase; iron staining; leukemia differentiation

1 Basic Positioning of Hematologic Cytochemical Staining

1.1 Detection Targets

(1) Intracellular enzyme activity

Hematologic cytochemical staining can demonstrate the activity of certain enzymes in myeloid cells, monocytes, lymphocytes, megakaryocytes, and erythroid cells, such as myeloperoxidase, specific esterase, nonspecific esterase, alkaline phosphatase, and acid phosphatase. These enzyme activities are associated with cell lineage and differentiation stage.

(2) Intracellular chemical components

Some staining methods are used to demonstrate glycogen, lipids, iron granules, and reticular-fiber-related components. For example, PAS staining is used to observe glycogen and glycoproteins, while iron staining is used to evaluate bone marrow iron stores and ring sideroblasts.

(3) Cellular functional status

Certain cytochemical reactions reflect cellular function or maturation status. For example, the neutrophil alkaline phosphatase score can help distinguish chronic myeloid leukemia from leukemoid reaction, while nonspecific esterase can suggest monocytic differentiation.

1.2 Methodological Characteristics

(1) Dependence on morphological background

Cytochemical staining must be interpreted together with smear morphology. The cell type showing positive granules, the staining intensity, and the percentage of positive cells all need to be evaluated microscopically in combination with cell size, nuclear morphology, cytoplasmic volume, granules, and maturation stage.

(2) Mostly semi-quantitative results

Most hematologic cytochemical staining results are reported as negative, weakly positive, positive, strongly positive, or as a score. They are essentially semi-quantitative or categorical interpretations and should not be directly equated with precise enzymatic activity quantification.

(3) Strong influence of sample quality

Bone marrow smear thickness, cellular integrity, anticoagulants, fixation conditions, staining solution freshness, incubation temperature, and reaction time can all affect staining results. Cytochemical staining requires highly consistent sample pretreatment.

Table 1 Main Types of Hematologic Cytochemical Staining

Staining Type	Main Detection Target	Typical Positive Cells	Main Use
Peroxidase staining (MPO/POX)	Myeloperoxidase	Granulocytic cells, some myeloid blasts	Preliminary differentiation of myeloid and lymphoid lineages
Sudan Black B staining (SBB)	Lipids, phospholipids, and myeloid granule-related components	Granulocytic cells, some monocytic cells	Auxiliary assessment of myeloid differentiation
Specific esterase staining	Chloroacetate esterase and related enzymes	Granulocytic cells	Identification of granulocytic differentiation
Nonspecific esterase staining	α-Naphthyl esterases	Monocytes, macrophages	Identification of monocytic differentiation
PAS staining	Glycogen, glycoproteins, polysaccharides	Abnormal erythroid cells, lymphoblasts, etc.	Evaluation of erythroleukemia, ALL, and some abnormal proliferations
Neutrophil alkaline phosphatase staining	Neutrophil alkaline phosphatase	Mature neutrophils	Auxiliary differentiation between CML and leukemoid reaction
Iron staining	Intracellular and extracellular iron	Bone marrow macrophages, sideroblasts	Evaluation of bone marrow iron stores and sideroblasts
Acid phosphatase staining	Acid phosphatase	Some lymphocytes, monocytes, hairy cells, etc.	Auxiliary assessment of specific lymphoproliferative diseases

2 Peroxidase Staining

2.1 Staining Principle

Peroxidase staining is mainly used to demonstrate myeloperoxidase activity. Myeloperoxidase is present in the azurophilic granules of granulocytic cells and some myeloid blasts. It can catalyze the oxidation of chromogenic substrates by hydrogen peroxide, forming yellow-brown, brown-black, or dark granular deposits.

The core significance of this reaction is to determine whether blasts show myeloid differentiation. In general, granulocytic cells are MPO-positive, monocytic cells may be weakly positive or negative, and lymphoid blasts are usually negative.

2.2 Application Scenarios

(1) Preliminary classification of acute leukemia

In the morphological diagnosis of acute leukemia, MPO positivity supports acute myeloid leukemia. MPO negativity suggests the need to consider acute lymphoblastic leukemia, undifferentiated acute leukemia, or some poorly differentiated AML. Results still need to be interpreted together with flow cytometric immunophenotyping and genetic testing.

(2) Assessment of myeloid differentiation

When some blasts show atypical morphology, MPO staining helps confirm whether myeloid granule enzyme activity is present. Positive granules are distributed in the cytoplasm and are often associated with the degree of cellular differentiation.

(3) Auxiliary evaluation of bone marrow after treatment

In post-treatment bone marrow, MPO staining can help identify regenerating granulocytic cells and residual abnormal cells, but it is not suitable as an independent method for minimal residual disease detection.

2.3 Interpretation Points

MPO interpretation should focus on the percentage of positive cells, granule intensity, and morphology of positive cells. Mature neutrophils are usually strongly positive. Weak positivity in blasts should be interpreted cautiously to avoid misinterpreting nonspecific deposits or background granules as true positivity.

Table 2 Interpretation of Peroxidase Staining Results

Cell Type	Common Reaction	Interpretation Significance	Notes
Neutrophils	Strongly positive	Feature of mature granulocytic cells	Can serve as an internal control
Myeloblasts	Negative to positive	Positivity supports myeloid differentiation	Poorly differentiated AML may be weakly positive or negative
Monocytes	Negative to weakly positive	Unstable; should be combined with NSE	Not suitable alone for determining monocytic differentiation
Lymphoblasts	Usually negative	Supports lymphoid direction	Requires immunophenotyping
Eosinophils	May be positive	Granules are prominent	Should be identified with morphology

3 Sudan Black B Staining

3.1 Staining Principle

Sudan Black B is a fat-soluble dye that stains intracellular lipids, phospholipids, and myeloid granule-related components. In hematologic cytochemistry, Sudan Black B is commonly used to demonstrate cytoplasmic granules in granulocytic cells, usually appearing as black or blue-black granules.

SBB has clinical uses similar to MPO, and both can be used to assess myeloid differentiation. SBB positivity usually supports granulocytic or some monocytic differentiation, while lymphoid cells are mostly negative.

3.2 Application Scenarios

(1) Auxiliary differentiation of acute myeloid leukemia

SBB positivity supports myeloid origin, especially when MPO results are weak or require supplementary assessment.

(2) Observation of granulocytic maturation stage

As granulocytic cells mature, SBB-positive granules usually become more prominent. Mature granulocytes are strongly positive, while early blasts may show weaker positivity.

(3) Complementary use with MPO

SBB detects lipids and granule-related components rather than MPO enzyme activity directly, so SBB and MPO results are not completely equivalent. In some cases, they confirm each other; in others, staining intensity may differ.

3.3 Interpretation Boundaries

SBB may show dark background staining, and lipids or nonspecific hydrophobic structures may interfere with interpretation. Results should be interpreted based on cell morphology, granule location, and control cell reactions rather than the overall color of the smear alone.

Table 3 Comparison Between MPO and SBB Staining

Comparison Dimension	MPO Staining	SBB Staining
Detection target	Myeloperoxidase activity	Lipids, phospholipids, and myeloid granule-related components
Typical positive cells	Granulocytic cells	Granulocytic cells, some monocytic cells
Value in myeloid assessment	High	High; often complementary to MPO
Positive appearance	Brown to dark cytoplasmic granules	Black or blue-black cytoplasmic granules
Main limitation	Enzyme activity is affected by fixation and reaction conditions	Background and nonspecific staining need to be controlled

4 Esterase Staining

4.1 Specific Esterase Staining

(1) Staining principle

Specific esterase staining is commonly represented by naphthol AS-D chloroacetate esterase staining and mainly demonstrates esterase activity in granulocytic cells. Positive reactions usually appear as red, purplish-red, or brown-red granular deposits localized in the cytoplasm.

(2) Application value

Specific esterase positivity supports granulocytic differentiation and can be used to identify granulocytic components in acute myeloid leukemia. Together with MPO and SBB, it forms an important cytochemical combination for assessing granulocytic differentiation.

(3) Interpretation notes

Mature granulocytes are often strongly positive, while myeloblasts may be weakly positive. If smears are overfixed or reaction conditions are inappropriate, enzyme activity may be reduced, causing false-negative results.

4.2 Nonspecific Esterase Staining

(1) Staining principle

Nonspecific esterase staining commonly uses α-naphthyl acetate or α-naphthyl butyrate as substrates and mainly demonstrates esterase activity associated with monocytes and macrophages. Positive reactions are often diffuse or granular cytoplasmic staining.

(2) Identification of monocytic lineage

Monocytes, immature monocytes, and some monocytoid leukemic cells often show NSE positivity. This staining is valuable in differentiating acute monocytic leukemia and acute myelomonocytic leukemia.

(3) Sodium fluoride inhibition test

Nonspecific esterase activity in monocytic cells is usually inhibited by sodium fluoride. If the NSE-positive reaction is markedly inhibited by NaF, monocytic differentiation is supported. If it is not inhibited, other cell origins or nonspecific reactions should be considered.

4.3 Combined Interpretation

In acute leukemia, combined use of specific esterase and nonspecific esterase helps distinguish granulocytic, monocytic, and mixed granulocytic-monocytic differentiation. Granulocytic cells are usually specific esterase-positive; monocytic cells are usually NSE-positive and NaF-inhibitable; acute myelomonocytic leukemia may show both positive cell populations.

Table 4 Application Differences of Esterase Staining

Staining Type	Common Substrate Direction	Main Positive Cells	Inhibition Feature	Main Use
Specific esterase	Naphthol chloroacetate esters	Granulocytic cells	NaF inhibition is usually not the core interpretation criterion	Identification of granulocytic differentiation
Nonspecific esterase	α-Naphthyl acetate, α-naphthyl butyrate	Monocytes, macrophages	Monocytic positivity is often inhibited by NaF	Identification of monocytic differentiation
Dual esterase staining	Combination of two substrate types	Granulocytic and monocytic cells	Can distinguish two types of positive reactions	Auxiliary assessment of acute myelomonocytic leukemia

5 PAS Staining

5.1 Staining Principle

PAS staining refers to periodic acid-Schiff staining. Periodic acid oxidizes vicinal diol structures in carbohydrates to generate aldehyde groups, which then react with Schiff reagent to form a purplish-red or magenta signal. In hematologic cells, PAS mainly demonstrates glycogen, glycoproteins, and some polysaccharide-related components.

5.2 Application Scenarios

(1) Acute lymphoblastic leukemia

Lymphoblasts may show PAS positivity, often with coarse granular or block-like positivity. This feature can serve as an auxiliary morphological indicator for ALL but cannot replace immunophenotyping.

(2) Erythroleukemia and abnormal erythroid proliferation

Abnormal erythroid cells may show PAS positivity, especially in cases of abnormal erythroblast proliferation. Normal erythroblasts are usually PAS-negative or weakly reactive, while abnormal positivity suggests dysplastic erythropoiesis.

(3) Megakaryocyte and platelet-related observation

Megakaryocytes and platelets may be PAS-positive, which can help identify the platelet system and some megakaryocytic abnormalities.

5.3 Interpretation Points

The PAS positivity pattern is more meaningful than positivity intensity alone. Diffuse, fine granular, coarse granular, or block-like positivity suggests different intracellular carbohydrate distribution patterns. Interpretation should be combined with cell lineage, morphological abnormalities, and other cytochemical results.

Table 5 Common PAS Staining Result Patterns

Cell Type	Common PAS Reaction	Interpretation Significance	Notes
Lymphoblasts	Granular or block-like positivity may be seen	Supports auxiliary assessment of ALL	Requires immunophenotyping
Normal erythroblasts	Mostly negative or weakly positive	Normal erythroid feature	Strong positivity suggests abnormal erythroid lineage
Abnormal erythroid cells	May be clearly positive	Supports dysplastic erythropoiesis	Should be combined with bone marrow morphology and genetics
Megakaryocytes	Often positive	Reflects abundant glycoproteins	Can help identify megakaryocytes
Granulocytic cells	May be weakly positive or nonspecific	Limited diagnostic specificity	Not a core marker for granulocytic identification

6 Neutrophil Alkaline Phosphatase Staining

6.1 Staining Principle

Neutrophil alkaline phosphatase staining is used to demonstrate alkaline phosphatase activity in mature neutrophils. Reaction products are usually localized in the cytoplasm of mature neutrophils, and results are generally scored based on staining intensity and the proportion of positive cells.

6.2 Clinical Applications

(1) Differentiation between CML and leukemoid reaction

The NAP score is usually decreased in chronic myeloid leukemia and often increased in leukemoid reaction. This indicator was once an important laboratory basis for differentiating the two.

(2) Evaluation of infection and inflammatory status

Severe infection, inflammatory stimulation, and stress states may increase neutrophil alkaline phosphatase activity, suggesting neutrophil functional activation.

(3) Auxiliary assessment of myeloproliferative diseases

NAP scoring can provide reference value for differentiating some myeloproliferative diseases, but modern diagnosis relies more on genetics, molecular markers, and comprehensive clinical assessment.

6.3 Interpretation Limitations

The NAP score is affected by infection, drugs, pregnancy, hormones, sample storage, and operating conditions. It cannot be used alone to diagnose CML or other myeloproliferative diseases and should be interpreted together with BCR-ABL1 testing, blood counts, bone marrow morphology, and clinical presentation.

Table 6 Common Interpretation of NAP Staining Results

Result Pattern	Common Background	Interpretation Direction	Notes
Decreased NAP score	Common in CML	Supports chronic myeloid leukemia direction	Requires BCR-ABL1 confirmation
Increased NAP score	Leukemoid reaction, infection, inflammation	Supports reactive granulocytosis	Should be combined with infection markers
Normal NAP score	Seen in multiple conditions	Limited diagnostic specificity	Should not be used alone to exclude disease
Strong positivity in mature neutrophils	Reactive activation	Functional activation	Strongly affected by clinical status

7 Iron Staining

7.1 Staining Principle

Bone marrow iron staining commonly uses the Prussian blue reaction to demonstrate ferric iron. Iron reacts with acidic ferrocyanide to form blue deposits, allowing observation of extracellular storage iron in bone marrow and intracellular iron granules in erythroblasts.

7.2 Application Scenarios

(1) Evaluation of bone marrow storage iron

Blue granules in bone marrow macrophages reflect storage iron status. Iron deficiency anemia often shows reduced or absent bone marrow storage iron.

(2) Observation of sideroblasts

Erythroblasts containing blue iron granules in the cytoplasm are called sideroblasts. If iron granules are arranged around the nucleus in a ring, they are called ring sideroblasts, which are important morphological clues in some myelodysplastic syndromes and sideroblastic anemia.

(3) Differentiation of anemia

Iron staining helps distinguish iron deficiency anemia, anemia of chronic disease, sideroblastic anemia, and some MDS-related anemias.

7.3 Interpretation Points

Iron staining requires separate evaluation of extracellular and intracellular iron. Extracellular iron reflects storage iron, while intracellular iron reflects erythroid iron utilization. Iron contamination of smears, improper decolorization, or insufficient marrow particles can all affect interpretation.

Table 7 Interpretation Directions of Bone Marrow Iron Staining

Observation Target	Positive Appearance	Main Significance	Common Application
Extracellular iron	Blue granules in macrophages or marrow particles	Storage iron level	Differentiation of iron deficiency anemia and anemia of chronic disease
Sideroblasts	Blue iron granules in erythroblast cytoplasm	Erythroid iron utilization status	Anemia classification and erythroid maturation evaluation
Ring sideroblasts	Iron granules arranged around the nucleus	Abnormal mitochondrial iron deposition	MDS, sideroblastic anemia
Negative or very little iron	Lack of storage iron	Supports iron deficiency	Should be combined with serum ferritin and clinical indicators

8 Acid Phosphatase and Other Special Stains

8.1 Acid Phosphatase Staining

Acid phosphatase staining can demonstrate acid phosphatase activity in some lymphocytes, monocytes, macrophages, and certain abnormal cells. It has auxiliary value in diseases such as hairy cell leukemia. Tartrate-resistant acid phosphatase (TRAP) reaction was once used as an auxiliary diagnostic method for hairy cell leukemia.

8.2 β-Glucuronidase Staining

β-Glucuronidase staining can reflect enzyme activity associated with parts of the monocyte-macrophage system and can be used as a supplementary indicator for monocytic differentiation, although its routine clinical use is less frequent than MPO, SBB, esterase, and PAS staining.

8.3 Enzyme Stains Other Than Alkaline Phosphatase

Some laboratories may also perform acid esterase, phosphatase, dehydrogenase, and other stains for specific research or auxiliary disease assessment. These methods require clearly defined detection purposes, positive controls, and interpretation criteria.

9 Combined Application of Hematologic Cytochemical Staining

9.1 Preliminary Differentiation of Acute Leukemia

In acute leukemia, MPO, SBB, specific esterase, nonspecific esterase, and PAS are commonly used to preliminarily distinguish myeloid, monocytic, and lymphoid differentiation. MPO or SBB positivity supports myeloid differentiation; NSE positivity with NaF inhibition supports monocytic differentiation; coarse granular or block-like PAS positivity may suggest lymphoblasts or abnormal erythroid features.

9.2 Assessment of AML Subtypes

In acute granulocytic leukemia, MPO, SBB, and specific esterase are often positive. In acute monocytic leukemia, nonspecific esterase positivity is more meaningful. In acute myelomonocytic leukemia, cytochemical features of both granulocytic and monocytic lineages may coexist.

9.3 Evaluation of Anemia and Erythroid Abnormalities

Iron staining and PAS staining can be used for anemia classification and evaluation of abnormal erythroid proliferation. Iron staining focuses on storage iron, sideroblasts, and ring sideroblasts; PAS staining may suggest dysplastic erythropoiesis and some erythroleukemia-related changes.

9.4 Auxiliary Assessment of Myeloproliferative Diseases

NAP staining can serve as an auxiliary method for evaluating neutrophil functional status and reactive granulocytosis. Chronic myeloid leukemia often shows a reduced NAP score, but modern diagnosis must be combined with molecular tests such as BCR-ABL1.

Table 8 Cytochemical Staining Combinations in Common Disease Scenarios

Disease or Scenario	Recommended Staining Combination	Typical Clues	Interpretation Focus
Acute myeloid leukemia	MPO, SBB, specific esterase	Myeloid cells positive	Requires flow cytometric immunophenotyping
Acute monocytic leukemia	NSE, NaF inhibition test, MPO	NSE-positive and inhibited by NaF	Distinguish monocytic from granulocytic differentiation
Acute myelomonocytic leukemia	Specific esterase, NSE, MPO	Granulocytic and monocytic reactions coexist	Focus on different positive cell populations
Acute lymphoblastic leukemia	PAS, MPO, SBB	PAS may be positive; MPO/SBB mostly negative	Cannot replace immunophenotyping
Iron deficiency anemia	Iron staining	Reduced or absent storage iron	Combine with ferritin and red cell indices
MDS with ring sideroblasts	Iron staining, PAS	Increased ring sideroblasts	Combine with morphology and genetics
CML vs leukemoid reaction	NAP staining	Low in CML, high in leukemoid reaction	Requires BCR-ABL1 confirmation

10 Quality Control and Common Problems

10.1 Smear Quality

Hematologic cytochemical staining requires smears of appropriate thickness, uniform cell distribution, and intact cell morphology. Excessively thick smears may cause uneven staining and high background; overly thin smears may contain too few positive cells, making scoring and classification difficult.

10.2 Fixation Conditions

Different cytochemical stains have different sensitivities to fixatives. Enzyme stains in particular require avoidance of overfixation, which can reduce enzyme activity. Fixation time, fixative type, and sample drying status should be strictly controlled according to the specific staining method.

10.3 Control Setup

Positive and negative controls should be included in each staining run. Mature neutrophils can serve as internal controls for MPO and SBB. Known positive samples can be used for quality control of esterase, PAS, NAP, and iron staining.

10.4 Result Interpretation

Cytochemical staining results should be interpreted together with cellular morphology, peripheral blood findings, bone marrow morphology, flow cytometric immunophenotyping, karyotyping, and molecular testing. A single positive or negative stain cannot independently establish a diagnosis of hematologic malignancy.

Table 9 Common Problems and Optimization Directions in Hematologic Cytochemical Staining

Problem	Possible Cause	Impact on Results	Optimization Direction
Overall weak enzyme staining	Overfixation, reagent failure, insufficient reaction time	Risk of false negatives	Optimize fixation and include positive controls
Deep background staining	Smear too thick, insufficient washing, stain precipitation	Difficult interpretation of positive granules	Improve smear quality and filter staining solution
Unclear positive granules	Improper reaction time, unstable chromogenic substrate	Difficult grading	Control incubation time and temperature
Large fluctuation in NAP score	Improper sample storage, insufficient cells counted	Poor comparability between groups	Standardize sampling and counting rules
False-positive iron staining	Exogenous iron contamination, slide contamination	Overestimation of storage iron	Use clean instruments and include blanks
Inconsistent PAS results	Unstable oxidation time or Schiff reagent condition	Bias in positivity intensity	Control periodic acid oxidation time and reagent freshness

11 Reagent Selection Related to Hematologic Cytochemical Staining

Table 10 Common Basic Reagents and Materials for Hematologic Cytochemical Staining

Product Category	Product Name	CAS No.	Role in the System	Applicable Direction
Peroxidase chromogenic substrate	3,3'-Diaminobenzidine (DAB)	91-95-2	Peroxidase chromogenic substrate	MPO/POX staining, enzyme histochemical visualization
Lipid dye	Sudan Black B	4197-25-5	Stains lipids, phospholipids, and myeloid granule-related components	SBB staining, auxiliary assessment of myeloid differentiation
Lipid dye	Sudan III	85-86-9	Demonstrates neutral lipids	Observation of lipid granules and fat components
Lipid dye	Sudan IV	85-83-6	Demonstrates neutral lipids	Lipid deposition and lipid droplet observation
PAS oxidant	Periodic acid	10450-60-9	Oxidizes vicinal diols in carbohydrates to form aldehyde groups	Oxidation step before PAS staining
Glycogen digestion control	Amylase	9000-90-2	Digests glycogen to verify the source of PAS positivity	PAS staining quality control and specificity validation
Iron staining reagent	Potassium ferrocyanide	14459-95-1	Forms Prussian blue reaction with ferric iron	Bone marrow iron staining
Nonspecific esterase substrate	α-Naphthyl acetate	830-81-9	NSE reaction substrate	Monocyte- and macrophage-related esterase staining
Nonspecific esterase substrate	α-Naphthyl butyrate	3121-70-8	NSE reaction substrate	Auxiliary assessment of monocytic differentiation
Specific esterase substrate	Naphthol AS-D chloroacetate	35245-26-2	Specific esterase reaction substrate	Identification of granulocytic differentiation
Azo coupling salt	Fast Blue RR Salt	14726-29-5	Couples with naphthol products for color development	Esterase and phosphatase staining
Azo coupling salt	Fast Garnet GBC Salt	101-89-3	Azo coupling chromogen	Esterase and phosphatase histochemistry
Azo coupling salt	Fast Red Violet LB Salt	32348-81-5	Forms red deposits by coupling	Esterase and phosphatase staining
Esterase inhibitor	Sodium fluoride	7681-49-4	Inhibits monocytic nonspecific esterase	NSE sodium fluoride inhibition test
Alkaline phosphatase substrate	Naphthol AS-BI phosphate	1919-91-1	Alkaline phosphatase chromogenic substrate	NAP staining
TRAP inhibition/differentiation reagent	L-Tartaric acid	87-69-4	Used for tartrate-resistant acid phosphatase differentiation	TRAP staining, auxiliary assessment of hairy cell leukemia

Table 11 Ready-to-Use Reagent Kits and Auxiliary Materials for Hematologic Cytochemical Staining

Product Category	Cat. No.	Product Name	Grade / Specification	Role in the System	Applicable Direction
PAS chromogenic reagent	S1516056	Schiff Reagent	BioReagent,Biological Stain,for microscopy	Reacts with aldehyde groups generated after periodic acid oxidation to produce a magenta signal	PAS staining, glycogen and glycoprotein demonstration; suitable for hematologic cytochemical PAS systems
Peroxidase staining	P1518603	Peroxidase Staining Solution (Oxidase WG-KI Method)	BioReagent,Biological Stain,for microscopy	Demonstrates intracellular peroxidase-related reactions	MPO/POX staining, auxiliary assessment of myeloid differentiation in acute leukemia
Peroxidase staining	P1518605	Peroxidase Staining Solution (Benzidine Method)	BioReagent,Biological Stain,for microscopy	Peroxidase catalyzes substrate oxidation to form chromogenic deposits	Granulocytic cell identification and auxiliary differentiation of myeloid blasts
Sudan Black B staining	S1508362	Sudan Black B Staining Solution	BioReagent,for microscopy,Biological Stain	Demonstrates intracellular lipids, phospholipids, and myeloid granule-related components	SBB staining, auxiliary differentiation between AML and ALL
Sudan Black B staining	S1508441	Sudan Black B Staining Solution	BioReagent,for microscopy,Biological Stain	Forms black or blue-black granular staining signals	Granulocytic differentiation, myeloid granule observation, hematologic cytochemical staining
PAS combined staining	A774824	AB-PAS staining kit	BioReagent, for microscopy, Biological Stain	Simultaneously demonstrates acidic mucosubstances and PAS-positive components	Observation of carbohydrate components in tissues/cells; extended PAS-related system
Glycogen PAS staining	G774821	Glycogen D-PAS Staining Solution (Amylase Digestion)	BioReagent, for microscopy, Biological Stain	Uses amylase digestion to verify whether PAS positivity originates from glycogen	Quality control for hematologic PAS staining and specificity validation of glycogen positivity
Glycogen PAS staining	G774820	Glycogen PAS staining kit	BioReagent, Biological Stain, for microscopy	Demonstrates glycogen, glycoproteins, and polysaccharide components	Observation of PAS positivity patterns in ALL, abnormal erythroid proliferation, erythroleukemia, etc.
Glycogen PAS staining	G774823	Glycogen PAS Staining Kit (Special For Cell)	BioReagent, Biological Stain, for microscopy	Optimized PAS staining system for cultured cell samples	Observation of glycogen and glycoprotein components in cultured hematologic cells or cell lines
Prussian blue iron staining	P113746	Prussian blue	Biological Stain	Chromogenic material related to iron staining	Iron staining-related material; suitable for method expansion in iron deposition observation
Prussian blue iron staining	P131065	Prussian blue soluble	Biological Stain	Chromogenic material related to iron staining	Prussian blue-related staining systems and iron deposition observation
Prussian blue iron staining	P1508698	Prussian Blue Staining Solution (DAB Enhancement Method)	BioReagent,for microscopy,Biological Stain	Enhances Prussian blue iron staining signals	Bone marrow iron staining, observation of weakly positive iron granules, enhanced iron deposition visualization
Prussian blue iron staining	P774842	Prussian Blue Staining Kit (Neutral Red)	BioReagent, Biological Stain, for microscopy	Demonstrates ferric iron and uses neutral red counterstaining for localization	Observation of bone marrow storage iron, sideroblasts, and tissue iron deposition
Prussian blue iron staining	P774832	Prussian Blue Staining Kit (Eosin)	BioReagent, Biological Stain, for microscopy	Combines Prussian blue iron reaction with eosin counterstaining	Bone marrow or tissue iron staining; auxiliary cellular morphology localization
Prussian blue iron staining	P774831	Prussian Blue Staining Kit (Nuclear Fast Red)	BioReagent, for microscopy, Biological Stain	Combines Prussian blue iron reaction with nuclear fast red counterstaining	Bone marrow iron staining, sideroblast identification, tissue iron deposition localization
Basic morphology staining	M743374	Wright-Giemsa Staining Kit	BioReagent, Biological Stain, for microscopy	Provides basic morphological background for blood and bone marrow cells	Combined interpretation with MPO, SBB, PAS, iron staining, and other cytochemical results
Mounting material	F1508973	Fischor Mounting Medium	BioReagent,for microscopy,Suitable for Immunofluorescence(IF),Suitable for Immunohistochemistry(IHC)	Mounting after staining to maintain microscopic observation condition	Hematologic cytochemical staining, histological staining, and image acquisition
Mounting material	M292692	mounting medium	Unscented	Routine mounting	Microscopic observation after smear or tissue section staining
Glycerol mounting	C1508971	Routine Glycerol Mounting Medium	BioReagent,for microscopy,Suitable for Immunofluorescence(IF),for fluorescence analysis	Aqueous or semi-aqueous mounting to preserve stained samples	Cell smears, fluorescence combined staining, or temporary observation
Glycerol-PBS mounting	G1508970	Glycerol PBS Mounting Medium	BioReagent,for microscopy,Suitable for Immunofluorescence(IF),for fluorescence analysis	Buffered glycerol mounting system	Smear observation after staining, fluorescent or enzyme-staining combined samples
Antifade mounting	A752105	Enhanced Antifade Mounting Medium	BioReagent, for fluorescence analysis, Suitable for Immunofluorescence(IF)	Reduces fluorescence signal decay	Cytochemical staining combined with immunofluorescence or fluorescent labeling experiments
Antifade mounting	A598329	Antifluorescent quencher		Protects fluorescence signal and reduces quenching	Fluorescent cytochemical staining and immunofluorescence combined observation
Antifade mounting	P1508975	Polyvinyl Alcohol Anti-Fluorescence Quenching Mounting Medium	Suitable for Immunofluorescence(IF),BioReagent,for microscopy,for fluorescence analysis	Improves storage stability of fluorescent samples	Fluorescent staining samples and immunofluorescence-combined cytochemical experiments
Glycerol mounting	P1508974	Polyvinyl Alcohol Glycerol Mounting Medium	BioReagent,for microscopy,Suitable for Immunofluorescence(IF),Suitable for Immunohistochemistry(IHC)	Provides a relatively stable mounting environment	Blood smears, tissue sections, and immunostained samples
Glycerol mounting	A1508972	Gum Arabic Glycerol Mounting Medium	BioReagent,for microscopy,Suitable for microbiology,Suitable for Immunofluorescence(IF),Suitable for Immunohistochemistry(IHC)	Traditional glycerol-based mounting system	Mounting and long-term observation of microscopic staining samples

The core value of hematologic cytochemical staining lies in combining cellular morphology with demonstration of functional components, providing directional evidence for the preliminary differentiation of hematologic diseases. In practice, smear quality, fixation conditions, positive controls, and interpretation standards should be kept consistent, and the results should be incorporated into an integrated diagnostic framework including morphology, immunophenotype, genetics, and molecular testing.