You sent your home test kit samples to the laboratory, the results have come back, and the numbers are above the guideline. Your first reaction is likely alarm — and that is completely understandable. But elevated results from a home test kit need context before you take action. A single sample above a threshold is not a crisis. It is information — and information is what empowers you to make good decisions. Here is a calm, step-by-step guide on what to do next.

Do Not Panic: Elevated Results Need Context

The most important thing to understand is that a home test kit result is a data point, not a diagnosis. A result of 0.8 µg/100cm² for methamphetamine on a single door frame tells you that contamination is present at that specific location — but it does not tell you the extent of contamination across the property, the source (use vs manufacturing), whether other rooms are affected, or what remediation is needed.

Similarly, a mould settle plate result identifying Aspergillus species in your bedroom air tells you that mould spores are present and what species they are — but it does not tell you the source of the mould, whether there is hidden growth in wall cavities, what the moisture source is, or how the spore concentration compares to calibrated professional air sampling.

Every laboratory result also carries a measurement uncertainty. For methamphetamine surface wipe analysis, this is typically ±20–30%. A result of 0.6 µg/100cm² with ±25% uncertainty means the true value lies somewhere between 0.45 and 0.75 µg/100cm². Results close to guideline thresholds should be interpreted cautiously — they indicate the need for further investigation, not necessarily immediate remediation.

Step 1: Review Your Results Carefully

Before doing anything else, read your laboratory report in full. Look for the following:

• The actual numbers — What is the concentration detected at each sample location? Compare each result against the relevant guideline (0.5 µg/100cm² for methamphetamine in residential properties).
• The measurement uncertainty — What is the reported uncertainty? Does the range overlap with the guideline threshold?
• The sample locations — Which areas of your property were tested? Remember that results only apply to the specific surfaces sampled.
• For mould results — What species were identified? Refer to our guide on home mould testing for species interpretation. Common species like Cladosporium at low levels are very different from toxigenic species like Stachybotrys.

If all results are marginally above the guideline (for meth: between 0.5 and 1.0 µg/100cm²), the situation warrants further investigation but is not an emergency. If results are significantly elevated (above 5 µg/100cm² for meth, or toxigenic mould species identified), professional assessment should be arranged promptly.

Step 2: Avoid Disturbing the Contamination

This is critical and counterintuitive. Your instinct may be to start cleaning immediately. Resist that urge. Inappropriate cleaning can make the situation worse.

For Methamphetamine Contamination

• Do not scrub walls or surfaces — Standard household cleaning will not effectively remove methamphetamine from porous materials. It may spread contamination across a wider area and drive residue deeper into porous substrates.
• Do not use bleach — Bleach does not break down methamphetamine. It can damage surfaces and create a false sense of security.
• Do not repaint — Painting over methamphetamine contamination does not seal it. Methamphetamine migrates through standard paint within months, and the contamination will resurface. Worse, it makes subsequent assessment more difficult.
• Do not remove carpet or materials — Tearing out carpet, curtains, or other materials without proper containment can release trapped residue into the air, increasing exposure for occupants.

For Mould Contamination

• Do not disturb visible mould growth — Scrubbing, brushing, or wiping mould releases millions of spores into the air, significantly increasing airborne exposure for occupants.
• Do not use fans or increase ventilation near mould — Air movement spreads spores to uncontaminated areas of the property.
• Do not apply bleach to porous surfaces — Bleach kills surface mould on non-porous materials but does not penetrate porous substrates (plasterboard, timber). The residual moisture from bleach application actually promotes mould regrowth.

The purpose of professional assessment is to determine what needs to be done. Acting before that assessment risks incomplete remediation, wasted expenditure, and potentially making the contamination harder to address.

Step 3: Engage a Qualified Professional

Not all “meth testers” or “mould inspectors” are equal. When selecting a professional assessor, look for the following qualifications and characteristics:

• MRACI CChem (Chartered Chemist) — This is the professional designation from the Royal Australian Chemical Institute indicating formal chemistry qualifications and professional standing. It is the gold standard for contamination assessment in Australia.
• Independence — The assessor should have no financial relationship with any remediation or cleaning company. An assessor who also offers remediation, or who receives referral fees from remediators, has a conflict of interest that compromises the objectivity of their findings. We have written extensively about this conflict.
• Use of NATA-accredited laboratories — All samples should be analysed by an independent NATA-accredited laboratory, not in-house or by an unaccredited facility. NATA accreditation ensures the laboratory operates under a quality management system with regular proficiency testing.
• Comprehensive methodology — The assessor should describe their approach: how many samples they will collect, where, what instruments they use (moisture meters, thermal cameras for mould; systematic wipe sampling for meth), and what their report will include.
• Experience and track record — Ask how long they have been conducting assessments, how many they have completed, and whether they have experience providing evidence in legal or insurance matters.

Step 4: Get a Comprehensive Professional Assessment

A professional assessment goes far beyond what a home kit can achieve. For methamphetamine contamination, the assessor will systematically sample every room and surface type to create a contamination map of the entire property. They will determine whether contamination patterns are consistent with use (smoking) or manufacturing — a critical distinction that affects remediation scope and cost by an order of magnitude. They will identify contamination reservoirs (HVAC systems, carpet, soft furnishings, porous building materials) and produce a detailed report with remediation recommendations.

For mould contamination, the assessor will conduct moisture mapping using calibrated instruments to identify the moisture source driving mould growth. They will use thermal imaging to detect hidden moisture and mould behind walls and in ceiling cavities. Air sampling will quantify what occupants are actually breathing. Surface sampling will identify species across all affected areas. The report will identify the root cause (the moisture source), the extent of contamination, and the remediation scope.

Step 5: Follow the Remediation Pathway

The correct remediation pathway involves three independent stages, and the word independent is deliberate:

1. Independent assessment — A qualified assessor (like Test Australia) determines the nature, extent, and source of contamination and recommends a remediation scope. The assessor does not perform the remediation.
2. Independent remediation — A qualified remediation contractor carries out the work according to the scope defined by the assessor. The remediator does not conduct the clearance testing.
3. Independent clearance — The original assessor (or another independent assessor) conducts post-remediation verification testing to confirm the property meets the relevant guidelines. The clearance assessor must be independent of the remediator.

This three-stage, arms-length model ensures that every party has a vested interest in getting it right. The assessor’s reputation depends on accurate findings. The remediator’s payment depends on passing clearance. The clearance assessor’s credibility depends on only certifying genuinely clean properties. When any of these roles are combined — when the same company assesses, remediates, and clears — the conflicts of interest are obvious and the property owner’s protection is compromised.

Test Australia operates exclusively in the assessment and clearance stages. We do not own, operate, or receive referral fees from any remediation or cleaning company. Our findings are impartial because our business model does not depend on finding contamination or recommending expensive remediation.

Insurance Considerations

If your property is insured and contamination may be covered under your policy, notify your insurer early in the process — ideally before commissioning a professional assessment. Key points:

• Early notification — Most insurance policies require prompt notification of potential claims. Delaying notification can jeopardise your claim.
• Professional reporting strengthens claims — A comprehensive report from a qualified, independent assessor provides the evidence insurers need to process claims. Home kit results alone are insufficient.
• Keep all documentation — Retain your home test kit results, laboratory reports, chain of custody forms, professional assessment reports, remediation quotes, and all correspondence. A complete paper trail supports your claim.
• Do not authorise remediation before insurer approval — Proceeding with remediation before your insurer has approved the scope may result in costs not being covered. Get written approval before work commences.

For guidance on contamination and insurance, see our detailed guide on home testing or contact us to discuss your specific circumstances.